28994a5852
machines. - Leave the long-term load balancer running by default once per second. - Enable stealing load from the idle thread only when the remote processor has more than two transferable tasks. Setting this to one further improves buildworld. Setting it higher improves mysql. - Remove the bogus pick_zero option. I had not intended to commit this. - Entirely disallow migration for threads with SRQ_YIELDING set. This balances out the extra migration allowed for with the load balancers. It also makes pick_pri perform better as I had anticipated. Tested by: Dmitry Morozovsky <marck@rinet.ru> Approved by: re
2555 lines
64 KiB
C
2555 lines
64 KiB
C
/*-
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* Copyright (c) 2002-2007, Jeffrey Roberson <jeff@freebsd.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice unmodified, this list of conditions, and the following
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* disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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* This file implements the ULE scheduler. ULE supports independent CPU
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* run queues and fine grain locking. It has superior interactive
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* performance under load even on uni-processor systems.
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*
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* etymology:
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* ULE is the last three letters in schedule. It owes it's name to a
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* generic user created for a scheduling system by Paul Mikesell at
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* Isilon Systems and a general lack of creativity on the part of the author.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include "opt_hwpmc_hooks.h"
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#include "opt_sched.h"
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/kdb.h>
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#include <sys/kernel.h>
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#include <sys/ktr.h>
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#include <sys/lock.h>
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#include <sys/mutex.h>
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#include <sys/proc.h>
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#include <sys/resource.h>
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#include <sys/resourcevar.h>
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#include <sys/sched.h>
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#include <sys/smp.h>
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#include <sys/sx.h>
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#include <sys/sysctl.h>
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#include <sys/sysproto.h>
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#include <sys/turnstile.h>
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#include <sys/umtx.h>
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#include <sys/vmmeter.h>
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#ifdef KTRACE
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#include <sys/uio.h>
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#include <sys/ktrace.h>
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#endif
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#ifdef HWPMC_HOOKS
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#include <sys/pmckern.h>
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#endif
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#include <machine/cpu.h>
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#include <machine/smp.h>
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#ifndef PREEMPTION
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#error "SCHED_ULE requires options PREEMPTION"
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#endif
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#define KTR_ULE 0
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/*
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* Thread scheduler specific section. All fields are protected
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* by the thread lock.
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*/
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struct td_sched {
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TAILQ_ENTRY(td_sched) ts_procq; /* Run queue. */
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struct thread *ts_thread; /* Active associated thread. */
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struct runq *ts_runq; /* Run-queue we're queued on. */
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short ts_flags; /* TSF_* flags. */
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u_char ts_rqindex; /* Run queue index. */
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u_char ts_cpu; /* CPU that we have affinity for. */
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int ts_slptick; /* Tick when we went to sleep. */
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int ts_slice; /* Ticks of slice remaining. */
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u_int ts_slptime; /* Number of ticks we vol. slept */
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u_int ts_runtime; /* Number of ticks we were running */
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/* The following variables are only used for pctcpu calculation */
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int ts_ltick; /* Last tick that we were running on */
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int ts_ftick; /* First tick that we were running on */
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int ts_ticks; /* Tick count */
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#ifdef SMP
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int ts_rltick; /* Real last tick, for affinity. */
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#endif
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};
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/* flags kept in ts_flags */
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#define TSF_BOUND 0x0001 /* Thread can not migrate. */
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#define TSF_XFERABLE 0x0002 /* Thread was added as transferable. */
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static struct td_sched td_sched0;
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/*
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* Cpu percentage computation macros and defines.
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*
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* SCHED_TICK_SECS: Number of seconds to average the cpu usage across.
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* SCHED_TICK_TARG: Number of hz ticks to average the cpu usage across.
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* SCHED_TICK_MAX: Maximum number of ticks before scaling back.
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* SCHED_TICK_SHIFT: Shift factor to avoid rounding away results.
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* SCHED_TICK_HZ: Compute the number of hz ticks for a given ticks count.
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* SCHED_TICK_TOTAL: Gives the amount of time we've been recording ticks.
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*/
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#define SCHED_TICK_SECS 10
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#define SCHED_TICK_TARG (hz * SCHED_TICK_SECS)
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#define SCHED_TICK_MAX (SCHED_TICK_TARG + hz)
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#define SCHED_TICK_SHIFT 10
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#define SCHED_TICK_HZ(ts) ((ts)->ts_ticks >> SCHED_TICK_SHIFT)
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#define SCHED_TICK_TOTAL(ts) (max((ts)->ts_ltick - (ts)->ts_ftick, hz))
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/*
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* These macros determine priorities for non-interactive threads. They are
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* assigned a priority based on their recent cpu utilization as expressed
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* by the ratio of ticks to the tick total. NHALF priorities at the start
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* and end of the MIN to MAX timeshare range are only reachable with negative
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* or positive nice respectively.
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*
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* PRI_RANGE: Priority range for utilization dependent priorities.
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* PRI_NRESV: Number of nice values.
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* PRI_TICKS: Compute a priority in PRI_RANGE from the ticks count and total.
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* PRI_NICE: Determines the part of the priority inherited from nice.
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*/
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#define SCHED_PRI_NRESV (PRIO_MAX - PRIO_MIN)
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#define SCHED_PRI_NHALF (SCHED_PRI_NRESV / 2)
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#define SCHED_PRI_MIN (PRI_MIN_TIMESHARE + SCHED_PRI_NHALF)
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#define SCHED_PRI_MAX (PRI_MAX_TIMESHARE - SCHED_PRI_NHALF)
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#define SCHED_PRI_RANGE (SCHED_PRI_MAX - SCHED_PRI_MIN)
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#define SCHED_PRI_TICKS(ts) \
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(SCHED_TICK_HZ((ts)) / \
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(roundup(SCHED_TICK_TOTAL((ts)), SCHED_PRI_RANGE) / SCHED_PRI_RANGE))
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#define SCHED_PRI_NICE(nice) (nice)
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/*
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* These determine the interactivity of a process. Interactivity differs from
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* cpu utilization in that it expresses the voluntary time slept vs time ran
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* while cpu utilization includes all time not running. This more accurately
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* models the intent of the thread.
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*
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* SLP_RUN_MAX: Maximum amount of sleep time + run time we'll accumulate
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* before throttling back.
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* SLP_RUN_FORK: Maximum slp+run time to inherit at fork time.
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* INTERACT_MAX: Maximum interactivity value. Smaller is better.
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* INTERACT_THRESH: Threshhold for placement on the current runq.
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*/
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#define SCHED_SLP_RUN_MAX ((hz * 5) << SCHED_TICK_SHIFT)
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#define SCHED_SLP_RUN_FORK ((hz / 2) << SCHED_TICK_SHIFT)
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#define SCHED_INTERACT_MAX (100)
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#define SCHED_INTERACT_HALF (SCHED_INTERACT_MAX / 2)
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#define SCHED_INTERACT_THRESH (30)
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/*
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* tickincr: Converts a stathz tick into a hz domain scaled by
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* the shift factor. Without the shift the error rate
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* due to rounding would be unacceptably high.
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* realstathz: stathz is sometimes 0 and run off of hz.
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* sched_slice: Runtime of each thread before rescheduling.
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* preempt_thresh: Priority threshold for preemption and remote IPIs.
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*/
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static int sched_interact = SCHED_INTERACT_THRESH;
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static int realstathz;
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static int tickincr;
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static int sched_slice;
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static int preempt_thresh = PRI_MIN_KERN;
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/*
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* tdq - per processor runqs and statistics. All fields are protected by the
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* tdq_lock. The load and lowpri may be accessed without to avoid excess
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* locking in sched_pickcpu();
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*/
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struct tdq {
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struct mtx tdq_lock; /* Protects all fields below. */
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struct runq tdq_realtime; /* real-time run queue. */
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struct runq tdq_timeshare; /* timeshare run queue. */
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struct runq tdq_idle; /* Queue of IDLE threads. */
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int tdq_load; /* Aggregate load. */
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u_char tdq_idx; /* Current insert index. */
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u_char tdq_ridx; /* Current removal index. */
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#ifdef SMP
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u_char tdq_lowpri; /* Lowest priority thread. */
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int tdq_transferable; /* Transferable thread count. */
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LIST_ENTRY(tdq) tdq_siblings; /* Next in tdq group. */
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struct tdq_group *tdq_group; /* Our processor group. */
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#else
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int tdq_sysload; /* For loadavg, !ITHD load. */
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#endif
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char tdq_name[16]; /* lock name. */
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} __aligned(64);
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#ifdef SMP
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/*
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* tdq groups are groups of processors which can cheaply share threads. When
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* one processor in the group goes idle it will check the runqs of the other
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* processors in its group prior to halting and waiting for an interrupt.
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* These groups are suitable for SMT (Symetric Multi-Threading) and not NUMA.
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* In a numa environment we'd want an idle bitmap per group and a two tiered
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* load balancer.
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*/
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struct tdq_group {
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int tdg_cpus; /* Count of CPUs in this tdq group. */
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cpumask_t tdg_cpumask; /* Mask of cpus in this group. */
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cpumask_t tdg_idlemask; /* Idle cpus in this group. */
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cpumask_t tdg_mask; /* Bit mask for first cpu. */
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int tdg_load; /* Total load of this group. */
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int tdg_transferable; /* Transferable load of this group. */
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LIST_HEAD(, tdq) tdg_members; /* Linked list of all members. */
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} __aligned(64);
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#define SCHED_AFFINITY_DEFAULT (max(1, hz / 300))
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#define SCHED_AFFINITY(ts) ((ts)->ts_rltick > ticks - affinity)
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/*
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* Run-time tunables.
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*/
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static int rebalance = 1;
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static int balance_secs = 1;
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static int pick_pri = 1;
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static int affinity;
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static int tryself = 1;
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static int steal_htt = 0;
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static int steal_idle = 1;
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static int steal_thresh = 2;
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static int topology = 0;
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/*
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* One thread queue per processor.
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*/
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static volatile cpumask_t tdq_idle;
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static int tdg_maxid;
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static struct tdq tdq_cpu[MAXCPU];
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static struct tdq_group tdq_groups[MAXCPU];
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static struct callout balco;
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static struct callout gbalco;
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#define TDQ_SELF() (&tdq_cpu[PCPU_GET(cpuid)])
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#define TDQ_CPU(x) (&tdq_cpu[(x)])
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#define TDQ_ID(x) ((x) - tdq_cpu)
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#define TDQ_GROUP(x) (&tdq_groups[(x)])
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#else /* !SMP */
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static struct tdq tdq_cpu;
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#define TDQ_ID(x) (0)
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#define TDQ_SELF() (&tdq_cpu)
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#define TDQ_CPU(x) (&tdq_cpu)
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#endif
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#define TDQ_LOCK_ASSERT(t, type) mtx_assert(TDQ_LOCKPTR((t)), (type))
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#define TDQ_LOCK(t) mtx_lock_spin(TDQ_LOCKPTR((t)))
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#define TDQ_LOCK_FLAGS(t, f) mtx_lock_spin_flags(TDQ_LOCKPTR((t)), (f))
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#define TDQ_UNLOCK(t) mtx_unlock_spin(TDQ_LOCKPTR((t)))
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#define TDQ_LOCKPTR(t) (&(t)->tdq_lock)
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static void sched_priority(struct thread *);
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static void sched_thread_priority(struct thread *, u_char);
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static int sched_interact_score(struct thread *);
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static void sched_interact_update(struct thread *);
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static void sched_interact_fork(struct thread *);
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static void sched_pctcpu_update(struct td_sched *);
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/* Operations on per processor queues */
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static struct td_sched * tdq_choose(struct tdq *);
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static void tdq_setup(struct tdq *);
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static void tdq_load_add(struct tdq *, struct td_sched *);
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static void tdq_load_rem(struct tdq *, struct td_sched *);
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static __inline void tdq_runq_add(struct tdq *, struct td_sched *, int);
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static __inline void tdq_runq_rem(struct tdq *, struct td_sched *);
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void tdq_print(int cpu);
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static void runq_print(struct runq *rq);
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static void tdq_add(struct tdq *, struct thread *, int);
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#ifdef SMP
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static void tdq_move(struct tdq *, struct tdq *);
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static int tdq_idled(struct tdq *);
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static void tdq_notify(struct td_sched *);
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static struct td_sched *tdq_steal(struct tdq *, int);
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static struct td_sched *runq_steal(struct runq *);
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static int sched_pickcpu(struct td_sched *, int);
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static void sched_balance(void *);
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static void sched_balance_groups(void *);
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static void sched_balance_group(struct tdq_group *);
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static void sched_balance_pair(struct tdq *, struct tdq *);
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static inline struct tdq *sched_setcpu(struct td_sched *, int, int);
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static inline struct mtx *thread_block_switch(struct thread *);
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static inline void thread_unblock_switch(struct thread *, struct mtx *);
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#define THREAD_CAN_MIGRATE(td) ((td)->td_pinned == 0)
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#endif
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static void sched_setup(void *dummy);
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SYSINIT(sched_setup, SI_SUB_RUN_QUEUE, SI_ORDER_FIRST, sched_setup, NULL)
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static void sched_initticks(void *dummy);
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SYSINIT(sched_initticks, SI_SUB_CLOCKS, SI_ORDER_THIRD, sched_initticks, NULL)
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/*
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* Print the threads waiting on a run-queue.
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*/
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static void
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runq_print(struct runq *rq)
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{
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struct rqhead *rqh;
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struct td_sched *ts;
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int pri;
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int j;
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int i;
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for (i = 0; i < RQB_LEN; i++) {
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printf("\t\trunq bits %d 0x%zx\n",
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i, rq->rq_status.rqb_bits[i]);
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for (j = 0; j < RQB_BPW; j++)
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if (rq->rq_status.rqb_bits[i] & (1ul << j)) {
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pri = j + (i << RQB_L2BPW);
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rqh = &rq->rq_queues[pri];
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TAILQ_FOREACH(ts, rqh, ts_procq) {
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printf("\t\t\ttd %p(%s) priority %d rqindex %d pri %d\n",
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ts->ts_thread, ts->ts_thread->td_proc->p_comm, ts->ts_thread->td_priority, ts->ts_rqindex, pri);
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}
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}
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}
|
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}
|
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|
|
/*
|
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* Print the status of a per-cpu thread queue. Should be a ddb show cmd.
|
|
*/
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void
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tdq_print(int cpu)
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{
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struct tdq *tdq;
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tdq = TDQ_CPU(cpu);
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|
|
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printf("tdq:\n");
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printf("\tlockptr %p\n", TDQ_LOCKPTR(tdq));
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printf("\tlock name %s\n", tdq->tdq_name);
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printf("\tload: %d\n", tdq->tdq_load);
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printf("\ttimeshare idx: %d\n", tdq->tdq_idx);
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printf("\ttimeshare ridx: %d\n", tdq->tdq_ridx);
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printf("\trealtime runq:\n");
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runq_print(&tdq->tdq_realtime);
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printf("\ttimeshare runq:\n");
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runq_print(&tdq->tdq_timeshare);
|
|
printf("\tidle runq:\n");
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runq_print(&tdq->tdq_idle);
|
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#ifdef SMP
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printf("\tload transferable: %d\n", tdq->tdq_transferable);
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printf("\tlowest priority: %d\n", tdq->tdq_lowpri);
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#endif
|
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}
|
|
|
|
#define TS_RQ_PPQ (((PRI_MAX_TIMESHARE - PRI_MIN_TIMESHARE) + 1) / RQ_NQS)
|
|
/*
|
|
* Add a thread to the actual run-queue. Keeps transferable counts up to
|
|
* date with what is actually on the run-queue. Selects the correct
|
|
* queue position for timeshare threads.
|
|
*/
|
|
static __inline void
|
|
tdq_runq_add(struct tdq *tdq, struct td_sched *ts, int flags)
|
|
{
|
|
TDQ_LOCK_ASSERT(tdq, MA_OWNED);
|
|
THREAD_LOCK_ASSERT(ts->ts_thread, MA_OWNED);
|
|
#ifdef SMP
|
|
if (THREAD_CAN_MIGRATE(ts->ts_thread)) {
|
|
tdq->tdq_transferable++;
|
|
tdq->tdq_group->tdg_transferable++;
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ts->ts_flags |= TSF_XFERABLE;
|
|
}
|
|
#endif
|
|
if (ts->ts_runq == &tdq->tdq_timeshare) {
|
|
u_char pri;
|
|
|
|
pri = ts->ts_thread->td_priority;
|
|
KASSERT(pri <= PRI_MAX_TIMESHARE && pri >= PRI_MIN_TIMESHARE,
|
|
("Invalid priority %d on timeshare runq", pri));
|
|
/*
|
|
* This queue contains only priorities between MIN and MAX
|
|
* realtime. Use the whole queue to represent these values.
|
|
*/
|
|
if ((flags & SRQ_BORROWING) == 0) {
|
|
pri = (pri - PRI_MIN_TIMESHARE) / TS_RQ_PPQ;
|
|
pri = (pri + tdq->tdq_idx) % RQ_NQS;
|
|
/*
|
|
* This effectively shortens the queue by one so we
|
|
* can have a one slot difference between idx and
|
|
* ridx while we wait for threads to drain.
|
|
*/
|
|
if (tdq->tdq_ridx != tdq->tdq_idx &&
|
|
pri == tdq->tdq_ridx)
|
|
pri = (unsigned char)(pri - 1) % RQ_NQS;
|
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} else
|
|
pri = tdq->tdq_ridx;
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runq_add_pri(ts->ts_runq, ts, pri, flags);
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|
} else
|
|
runq_add(ts->ts_runq, ts, flags);
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|
}
|
|
|
|
/*
|
|
* Remove a thread from a run-queue. This typically happens when a thread
|
|
* is selected to run. Running threads are not on the queue and the
|
|
* transferable count does not reflect them.
|
|
*/
|
|
static __inline void
|
|
tdq_runq_rem(struct tdq *tdq, struct td_sched *ts)
|
|
{
|
|
TDQ_LOCK_ASSERT(tdq, MA_OWNED);
|
|
KASSERT(ts->ts_runq != NULL,
|
|
("tdq_runq_remove: thread %p null ts_runq", ts->ts_thread));
|
|
#ifdef SMP
|
|
if (ts->ts_flags & TSF_XFERABLE) {
|
|
tdq->tdq_transferable--;
|
|
tdq->tdq_group->tdg_transferable--;
|
|
ts->ts_flags &= ~TSF_XFERABLE;
|
|
}
|
|
#endif
|
|
if (ts->ts_runq == &tdq->tdq_timeshare) {
|
|
if (tdq->tdq_idx != tdq->tdq_ridx)
|
|
runq_remove_idx(ts->ts_runq, ts, &tdq->tdq_ridx);
|
|
else
|
|
runq_remove_idx(ts->ts_runq, ts, NULL);
|
|
/*
|
|
* For timeshare threads we update the priority here so
|
|
* the priority reflects the time we've been sleeping.
|
|
*/
|
|
ts->ts_ltick = ticks;
|
|
sched_pctcpu_update(ts);
|
|
sched_priority(ts->ts_thread);
|
|
} else
|
|
runq_remove(ts->ts_runq, ts);
|
|
}
|
|
|
|
/*
|
|
* Load is maintained for all threads RUNNING and ON_RUNQ. Add the load
|
|
* for this thread to the referenced thread queue.
|
|
*/
|
|
static void
|
|
tdq_load_add(struct tdq *tdq, struct td_sched *ts)
|
|
{
|
|
int class;
|
|
|
|
TDQ_LOCK_ASSERT(tdq, MA_OWNED);
|
|
THREAD_LOCK_ASSERT(ts->ts_thread, MA_OWNED);
|
|
class = PRI_BASE(ts->ts_thread->td_pri_class);
|
|
tdq->tdq_load++;
|
|
CTR2(KTR_SCHED, "cpu %jd load: %d", TDQ_ID(tdq), tdq->tdq_load);
|
|
if (class != PRI_ITHD &&
|
|
(ts->ts_thread->td_proc->p_flag & P_NOLOAD) == 0)
|
|
#ifdef SMP
|
|
tdq->tdq_group->tdg_load++;
|
|
#else
|
|
tdq->tdq_sysload++;
|
|
#endif
|
|
}
|
|
|
|
/*
|
|
* Remove the load from a thread that is transitioning to a sleep state or
|
|
* exiting.
|
|
*/
|
|
static void
|
|
tdq_load_rem(struct tdq *tdq, struct td_sched *ts)
|
|
{
|
|
int class;
|
|
|
|
THREAD_LOCK_ASSERT(ts->ts_thread, MA_OWNED);
|
|
TDQ_LOCK_ASSERT(tdq, MA_OWNED);
|
|
class = PRI_BASE(ts->ts_thread->td_pri_class);
|
|
if (class != PRI_ITHD &&
|
|
(ts->ts_thread->td_proc->p_flag & P_NOLOAD) == 0)
|
|
#ifdef SMP
|
|
tdq->tdq_group->tdg_load--;
|
|
#else
|
|
tdq->tdq_sysload--;
|
|
#endif
|
|
KASSERT(tdq->tdq_load != 0,
|
|
("tdq_load_rem: Removing with 0 load on queue %d", (int)TDQ_ID(tdq)));
|
|
tdq->tdq_load--;
|
|
CTR1(KTR_SCHED, "load: %d", tdq->tdq_load);
|
|
ts->ts_runq = NULL;
|
|
}
|
|
|
|
#ifdef SMP
|
|
/*
|
|
* sched_balance is a simple CPU load balancing algorithm. It operates by
|
|
* finding the least loaded and most loaded cpu and equalizing their load
|
|
* by migrating some processes.
|
|
*
|
|
* Dealing only with two CPUs at a time has two advantages. Firstly, most
|
|
* installations will only have 2 cpus. Secondly, load balancing too much at
|
|
* once can have an unpleasant effect on the system. The scheduler rarely has
|
|
* enough information to make perfect decisions. So this algorithm chooses
|
|
* simplicity and more gradual effects on load in larger systems.
|
|
*
|
|
*/
|
|
static void
|
|
sched_balance(void *arg)
|
|
{
|
|
struct tdq_group *high;
|
|
struct tdq_group *low;
|
|
struct tdq_group *tdg;
|
|
int cnt;
|
|
int i;
|
|
|
|
callout_reset(&balco, max(hz / 2, random() % (hz * balance_secs)),
|
|
sched_balance, NULL);
|
|
if (smp_started == 0 || rebalance == 0)
|
|
return;
|
|
low = high = NULL;
|
|
i = random() % (tdg_maxid + 1);
|
|
for (cnt = 0; cnt <= tdg_maxid; cnt++) {
|
|
tdg = TDQ_GROUP(i);
|
|
/*
|
|
* Find the CPU with the highest load that has some
|
|
* threads to transfer.
|
|
*/
|
|
if ((high == NULL || tdg->tdg_load > high->tdg_load)
|
|
&& tdg->tdg_transferable)
|
|
high = tdg;
|
|
if (low == NULL || tdg->tdg_load < low->tdg_load)
|
|
low = tdg;
|
|
if (++i > tdg_maxid)
|
|
i = 0;
|
|
}
|
|
if (low != NULL && high != NULL && high != low)
|
|
sched_balance_pair(LIST_FIRST(&high->tdg_members),
|
|
LIST_FIRST(&low->tdg_members));
|
|
}
|
|
|
|
/*
|
|
* Balance load between CPUs in a group. Will only migrate within the group.
|
|
*/
|
|
static void
|
|
sched_balance_groups(void *arg)
|
|
{
|
|
int i;
|
|
|
|
callout_reset(&gbalco, max(hz / 2, random() % (hz * balance_secs)),
|
|
sched_balance_groups, NULL);
|
|
if (smp_started == 0 || rebalance == 0)
|
|
return;
|
|
for (i = 0; i <= tdg_maxid; i++)
|
|
sched_balance_group(TDQ_GROUP(i));
|
|
}
|
|
|
|
/*
|
|
* Finds the greatest imbalance between two tdqs in a group.
|
|
*/
|
|
static void
|
|
sched_balance_group(struct tdq_group *tdg)
|
|
{
|
|
struct tdq *tdq;
|
|
struct tdq *high;
|
|
struct tdq *low;
|
|
int load;
|
|
|
|
if (tdg->tdg_transferable == 0)
|
|
return;
|
|
low = NULL;
|
|
high = NULL;
|
|
LIST_FOREACH(tdq, &tdg->tdg_members, tdq_siblings) {
|
|
load = tdq->tdq_load;
|
|
if (high == NULL || load > high->tdq_load)
|
|
high = tdq;
|
|
if (low == NULL || load < low->tdq_load)
|
|
low = tdq;
|
|
}
|
|
if (high != NULL && low != NULL && high != low)
|
|
sched_balance_pair(high, low);
|
|
}
|
|
|
|
/*
|
|
* Lock two thread queues using their address to maintain lock order.
|
|
*/
|
|
static void
|
|
tdq_lock_pair(struct tdq *one, struct tdq *two)
|
|
{
|
|
if (one < two) {
|
|
TDQ_LOCK(one);
|
|
TDQ_LOCK_FLAGS(two, MTX_DUPOK);
|
|
} else {
|
|
TDQ_LOCK(two);
|
|
TDQ_LOCK_FLAGS(one, MTX_DUPOK);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Transfer load between two imbalanced thread queues.
|
|
*/
|
|
static void
|
|
sched_balance_pair(struct tdq *high, struct tdq *low)
|
|
{
|
|
int transferable;
|
|
int high_load;
|
|
int low_load;
|
|
int move;
|
|
int diff;
|
|
int i;
|
|
|
|
tdq_lock_pair(high, low);
|
|
/*
|
|
* If we're transfering within a group we have to use this specific
|
|
* tdq's transferable count, otherwise we can steal from other members
|
|
* of the group.
|
|
*/
|
|
if (high->tdq_group == low->tdq_group) {
|
|
transferable = high->tdq_transferable;
|
|
high_load = high->tdq_load;
|
|
low_load = low->tdq_load;
|
|
} else {
|
|
transferable = high->tdq_group->tdg_transferable;
|
|
high_load = high->tdq_group->tdg_load;
|
|
low_load = low->tdq_group->tdg_load;
|
|
}
|
|
/*
|
|
* Determine what the imbalance is and then adjust that to how many
|
|
* threads we actually have to give up (transferable).
|
|
*/
|
|
if (transferable != 0) {
|
|
diff = high_load - low_load;
|
|
move = diff / 2;
|
|
if (diff & 0x1)
|
|
move++;
|
|
move = min(move, transferable);
|
|
for (i = 0; i < move; i++)
|
|
tdq_move(high, low);
|
|
}
|
|
TDQ_UNLOCK(high);
|
|
TDQ_UNLOCK(low);
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* Move a thread from one thread queue to another.
|
|
*/
|
|
static void
|
|
tdq_move(struct tdq *from, struct tdq *to)
|
|
{
|
|
struct td_sched *ts;
|
|
struct thread *td;
|
|
struct tdq *tdq;
|
|
int cpu;
|
|
|
|
tdq = from;
|
|
cpu = TDQ_ID(to);
|
|
ts = tdq_steal(tdq, 1);
|
|
if (ts == NULL) {
|
|
struct tdq_group *tdg;
|
|
|
|
tdg = tdq->tdq_group;
|
|
LIST_FOREACH(tdq, &tdg->tdg_members, tdq_siblings) {
|
|
if (tdq == from || tdq->tdq_transferable == 0)
|
|
continue;
|
|
ts = tdq_steal(tdq, 1);
|
|
break;
|
|
}
|
|
if (ts == NULL)
|
|
return;
|
|
}
|
|
if (tdq == to)
|
|
return;
|
|
td = ts->ts_thread;
|
|
/*
|
|
* Although the run queue is locked the thread may be blocked. Lock
|
|
* it to clear this.
|
|
*/
|
|
thread_lock(td);
|
|
/* Drop recursive lock on from. */
|
|
TDQ_UNLOCK(from);
|
|
sched_rem(td);
|
|
ts->ts_cpu = cpu;
|
|
td->td_lock = TDQ_LOCKPTR(to);
|
|
tdq_add(to, td, SRQ_YIELDING);
|
|
tdq_notify(ts);
|
|
}
|
|
|
|
/*
|
|
* This tdq has idled. Try to steal a thread from another cpu and switch
|
|
* to it.
|
|
*/
|
|
static int
|
|
tdq_idled(struct tdq *tdq)
|
|
{
|
|
struct tdq_group *tdg;
|
|
struct tdq *steal;
|
|
struct td_sched *ts;
|
|
struct thread *td;
|
|
int highload;
|
|
int highcpu;
|
|
int load;
|
|
int cpu;
|
|
|
|
/* We don't want to be preempted while we're iterating over tdqs */
|
|
spinlock_enter();
|
|
tdg = tdq->tdq_group;
|
|
/*
|
|
* If we're in a cpu group, try and steal threads from another cpu in
|
|
* the group before idling.
|
|
*/
|
|
if (steal_htt && tdg->tdg_cpus > 1 && tdg->tdg_transferable) {
|
|
LIST_FOREACH(steal, &tdg->tdg_members, tdq_siblings) {
|
|
if (steal == tdq || steal->tdq_transferable == 0)
|
|
continue;
|
|
TDQ_LOCK(steal);
|
|
ts = tdq_steal(steal, 0);
|
|
if (ts)
|
|
goto steal;
|
|
TDQ_UNLOCK(steal);
|
|
}
|
|
}
|
|
for (;;) {
|
|
if (steal_idle == 0)
|
|
break;
|
|
highcpu = 0;
|
|
highload = 0;
|
|
for (cpu = 0; cpu <= mp_maxid; cpu++) {
|
|
if (CPU_ABSENT(cpu))
|
|
continue;
|
|
steal = TDQ_CPU(cpu);
|
|
load = TDQ_CPU(cpu)->tdq_transferable;
|
|
if (load < highload)
|
|
continue;
|
|
highload = load;
|
|
highcpu = cpu;
|
|
}
|
|
if (highload < steal_thresh)
|
|
break;
|
|
steal = TDQ_CPU(highcpu);
|
|
TDQ_LOCK(steal);
|
|
if (steal->tdq_transferable >= steal_thresh &&
|
|
(ts = tdq_steal(steal, 1)) != NULL)
|
|
goto steal;
|
|
TDQ_UNLOCK(steal);
|
|
break;
|
|
}
|
|
spinlock_exit();
|
|
return (1);
|
|
steal:
|
|
td = ts->ts_thread;
|
|
thread_lock(td);
|
|
spinlock_exit();
|
|
MPASS(td->td_lock == TDQ_LOCKPTR(steal));
|
|
TDQ_UNLOCK(steal);
|
|
sched_rem(td);
|
|
sched_setcpu(ts, PCPU_GET(cpuid), SRQ_YIELDING);
|
|
tdq_add(tdq, td, SRQ_YIELDING);
|
|
MPASS(td->td_lock == curthread->td_lock);
|
|
mi_switch(SW_VOL, NULL);
|
|
thread_unlock(curthread);
|
|
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* Notify a remote cpu of new work. Sends an IPI if criteria are met.
|
|
*/
|
|
static void
|
|
tdq_notify(struct td_sched *ts)
|
|
{
|
|
struct thread *ctd;
|
|
struct pcpu *pcpu;
|
|
int cpri;
|
|
int pri;
|
|
int cpu;
|
|
|
|
cpu = ts->ts_cpu;
|
|
pri = ts->ts_thread->td_priority;
|
|
pcpu = pcpu_find(cpu);
|
|
ctd = pcpu->pc_curthread;
|
|
cpri = ctd->td_priority;
|
|
|
|
/*
|
|
* If our priority is not better than the current priority there is
|
|
* nothing to do.
|
|
*/
|
|
if (pri > cpri)
|
|
return;
|
|
/*
|
|
* Always IPI idle.
|
|
*/
|
|
if (cpri > PRI_MIN_IDLE)
|
|
goto sendipi;
|
|
/*
|
|
* If we're realtime or better and there is timeshare or worse running
|
|
* send an IPI.
|
|
*/
|
|
if (pri < PRI_MAX_REALTIME && cpri > PRI_MAX_REALTIME)
|
|
goto sendipi;
|
|
/*
|
|
* Otherwise only IPI if we exceed the threshold.
|
|
*/
|
|
if (pri > preempt_thresh)
|
|
return;
|
|
sendipi:
|
|
ctd->td_flags |= TDF_NEEDRESCHED;
|
|
ipi_selected(1 << cpu, IPI_PREEMPT);
|
|
}
|
|
|
|
/*
|
|
* Steals load from a timeshare queue. Honors the rotating queue head
|
|
* index.
|
|
*/
|
|
static struct td_sched *
|
|
runq_steal_from(struct runq *rq, u_char start)
|
|
{
|
|
struct td_sched *ts;
|
|
struct rqbits *rqb;
|
|
struct rqhead *rqh;
|
|
int first;
|
|
int bit;
|
|
int pri;
|
|
int i;
|
|
|
|
rqb = &rq->rq_status;
|
|
bit = start & (RQB_BPW -1);
|
|
pri = 0;
|
|
first = 0;
|
|
again:
|
|
for (i = RQB_WORD(start); i < RQB_LEN; bit = 0, i++) {
|
|
if (rqb->rqb_bits[i] == 0)
|
|
continue;
|
|
if (bit != 0) {
|
|
for (pri = bit; pri < RQB_BPW; pri++)
|
|
if (rqb->rqb_bits[i] & (1ul << pri))
|
|
break;
|
|
if (pri >= RQB_BPW)
|
|
continue;
|
|
} else
|
|
pri = RQB_FFS(rqb->rqb_bits[i]);
|
|
pri += (i << RQB_L2BPW);
|
|
rqh = &rq->rq_queues[pri];
|
|
TAILQ_FOREACH(ts, rqh, ts_procq) {
|
|
if (first && THREAD_CAN_MIGRATE(ts->ts_thread))
|
|
return (ts);
|
|
first = 1;
|
|
}
|
|
}
|
|
if (start != 0) {
|
|
start = 0;
|
|
goto again;
|
|
}
|
|
|
|
return (NULL);
|
|
}
|
|
|
|
/*
|
|
* Steals load from a standard linear queue.
|
|
*/
|
|
static struct td_sched *
|
|
runq_steal(struct runq *rq)
|
|
{
|
|
struct rqhead *rqh;
|
|
struct rqbits *rqb;
|
|
struct td_sched *ts;
|
|
int word;
|
|
int bit;
|
|
|
|
rqb = &rq->rq_status;
|
|
for (word = 0; word < RQB_LEN; word++) {
|
|
if (rqb->rqb_bits[word] == 0)
|
|
continue;
|
|
for (bit = 0; bit < RQB_BPW; bit++) {
|
|
if ((rqb->rqb_bits[word] & (1ul << bit)) == 0)
|
|
continue;
|
|
rqh = &rq->rq_queues[bit + (word << RQB_L2BPW)];
|
|
TAILQ_FOREACH(ts, rqh, ts_procq)
|
|
if (THREAD_CAN_MIGRATE(ts->ts_thread))
|
|
return (ts);
|
|
}
|
|
}
|
|
return (NULL);
|
|
}
|
|
|
|
/*
|
|
* Attempt to steal a thread in priority order from a thread queue.
|
|
*/
|
|
static struct td_sched *
|
|
tdq_steal(struct tdq *tdq, int stealidle)
|
|
{
|
|
struct td_sched *ts;
|
|
|
|
TDQ_LOCK_ASSERT(tdq, MA_OWNED);
|
|
if ((ts = runq_steal(&tdq->tdq_realtime)) != NULL)
|
|
return (ts);
|
|
if ((ts = runq_steal_from(&tdq->tdq_timeshare, tdq->tdq_ridx)) != NULL)
|
|
return (ts);
|
|
if (stealidle)
|
|
return (runq_steal(&tdq->tdq_idle));
|
|
return (NULL);
|
|
}
|
|
|
|
/*
|
|
* Sets the thread lock and ts_cpu to match the requested cpu. Unlocks the
|
|
* current lock and returns with the assigned queue locked. If this is
|
|
* via sched_switch() we leave the thread in a blocked state as an
|
|
* optimization.
|
|
*/
|
|
static inline struct tdq *
|
|
sched_setcpu(struct td_sched *ts, int cpu, int flags)
|
|
{
|
|
struct thread *td;
|
|
struct tdq *tdq;
|
|
|
|
THREAD_LOCK_ASSERT(ts->ts_thread, MA_OWNED);
|
|
|
|
tdq = TDQ_CPU(cpu);
|
|
td = ts->ts_thread;
|
|
ts->ts_cpu = cpu;
|
|
if (td->td_lock == TDQ_LOCKPTR(tdq))
|
|
return (tdq);
|
|
#ifdef notyet
|
|
/*
|
|
* If the thread isn't running it's lockptr is a
|
|
* turnstile or a sleepqueue. We can just lock_set without
|
|
* blocking.
|
|
*/
|
|
if (TD_CAN_RUN(td)) {
|
|
TDQ_LOCK(tdq);
|
|
thread_lock_set(td, TDQ_LOCKPTR(tdq));
|
|
return (tdq);
|
|
}
|
|
#endif
|
|
/*
|
|
* The hard case, migration, we need to block the thread first to
|
|
* prevent order reversals with other cpus locks.
|
|
*/
|
|
thread_lock_block(td);
|
|
TDQ_LOCK(tdq);
|
|
/* Return to sched_switch() with the lock still blocked */
|
|
if ((flags & SRQ_OURSELF) == 0)
|
|
thread_lock_unblock(td, TDQ_LOCKPTR(tdq));
|
|
return (tdq);
|
|
}
|
|
|
|
/*
|
|
* Find the thread queue running the lowest priority thread.
|
|
*/
|
|
static int
|
|
tdq_lowestpri(void)
|
|
{
|
|
struct tdq *tdq;
|
|
int lowpri;
|
|
int lowcpu;
|
|
int lowload;
|
|
int load;
|
|
int cpu;
|
|
int pri;
|
|
|
|
lowload = 0;
|
|
lowpri = lowcpu = 0;
|
|
for (cpu = 0; cpu <= mp_maxid; cpu++) {
|
|
if (CPU_ABSENT(cpu))
|
|
continue;
|
|
tdq = TDQ_CPU(cpu);
|
|
pri = tdq->tdq_lowpri;
|
|
load = TDQ_CPU(cpu)->tdq_load;
|
|
CTR4(KTR_ULE,
|
|
"cpu %d pri %d lowcpu %d lowpri %d",
|
|
cpu, pri, lowcpu, lowpri);
|
|
if (pri < lowpri)
|
|
continue;
|
|
if (lowpri && lowpri == pri && load > lowload)
|
|
continue;
|
|
lowpri = pri;
|
|
lowcpu = cpu;
|
|
lowload = load;
|
|
}
|
|
|
|
return (lowcpu);
|
|
}
|
|
|
|
/*
|
|
* Find the thread queue with the least load.
|
|
*/
|
|
static int
|
|
tdq_lowestload(void)
|
|
{
|
|
struct tdq *tdq;
|
|
int lowload;
|
|
int lowpri;
|
|
int lowcpu;
|
|
int load;
|
|
int cpu;
|
|
int pri;
|
|
|
|
lowcpu = 0;
|
|
lowload = TDQ_CPU(0)->tdq_load;
|
|
lowpri = TDQ_CPU(0)->tdq_lowpri;
|
|
for (cpu = 1; cpu <= mp_maxid; cpu++) {
|
|
if (CPU_ABSENT(cpu))
|
|
continue;
|
|
tdq = TDQ_CPU(cpu);
|
|
load = tdq->tdq_load;
|
|
pri = tdq->tdq_lowpri;
|
|
CTR4(KTR_ULE, "cpu %d load %d lowcpu %d lowload %d",
|
|
cpu, load, lowcpu, lowload);
|
|
if (load > lowload)
|
|
continue;
|
|
if (load == lowload && pri < lowpri)
|
|
continue;
|
|
lowcpu = cpu;
|
|
lowload = load;
|
|
lowpri = pri;
|
|
}
|
|
|
|
return (lowcpu);
|
|
}
|
|
|
|
/*
|
|
* Pick the destination cpu for sched_add(). Respects affinity and makes
|
|
* a determination based on load or priority of available processors.
|
|
*/
|
|
static int
|
|
sched_pickcpu(struct td_sched *ts, int flags)
|
|
{
|
|
struct tdq *tdq;
|
|
int self;
|
|
int pri;
|
|
int cpu;
|
|
|
|
cpu = self = PCPU_GET(cpuid);
|
|
if (smp_started == 0)
|
|
return (self);
|
|
/*
|
|
* Don't migrate a running thread from sched_switch().
|
|
*/
|
|
if (flags & SRQ_OURSELF) {
|
|
CTR1(KTR_ULE, "YIELDING %d",
|
|
curthread->td_priority);
|
|
return (self);
|
|
}
|
|
pri = ts->ts_thread->td_priority;
|
|
cpu = ts->ts_cpu;
|
|
/*
|
|
* Regardless of affinity, if the last cpu is idle send it there.
|
|
*/
|
|
tdq = TDQ_CPU(cpu);
|
|
if (tdq->tdq_lowpri > PRI_MIN_IDLE) {
|
|
CTR5(KTR_ULE,
|
|
"ts_cpu %d idle, ltick %d ticks %d pri %d curthread %d",
|
|
ts->ts_cpu, ts->ts_rltick, ticks, pri,
|
|
tdq->tdq_lowpri);
|
|
return (ts->ts_cpu);
|
|
}
|
|
/*
|
|
* If we have affinity, try to place it on the cpu we last ran on.
|
|
*/
|
|
if (SCHED_AFFINITY(ts) && tdq->tdq_lowpri > pri) {
|
|
CTR5(KTR_ULE,
|
|
"affinity for %d, ltick %d ticks %d pri %d curthread %d",
|
|
ts->ts_cpu, ts->ts_rltick, ticks, pri,
|
|
tdq->tdq_lowpri);
|
|
return (ts->ts_cpu);
|
|
}
|
|
/*
|
|
* Look for an idle group.
|
|
*/
|
|
CTR1(KTR_ULE, "tdq_idle %X", tdq_idle);
|
|
cpu = ffs(tdq_idle);
|
|
if (cpu)
|
|
return (--cpu);
|
|
/*
|
|
* If there are no idle cores see if we can run the thread locally. This may
|
|
* improve locality among sleepers and wakers when there is shared data.
|
|
*/
|
|
if (tryself && pri < curthread->td_priority) {
|
|
CTR1(KTR_ULE, "tryself %d",
|
|
curthread->td_priority);
|
|
return (self);
|
|
}
|
|
/*
|
|
* Now search for the cpu running the lowest priority thread with
|
|
* the least load.
|
|
*/
|
|
if (pick_pri)
|
|
cpu = tdq_lowestpri();
|
|
else
|
|
cpu = tdq_lowestload();
|
|
return (cpu);
|
|
}
|
|
|
|
#endif /* SMP */
|
|
|
|
/*
|
|
* Pick the highest priority task we have and return it.
|
|
*/
|
|
static struct td_sched *
|
|
tdq_choose(struct tdq *tdq)
|
|
{
|
|
struct td_sched *ts;
|
|
|
|
TDQ_LOCK_ASSERT(tdq, MA_OWNED);
|
|
ts = runq_choose(&tdq->tdq_realtime);
|
|
if (ts != NULL)
|
|
return (ts);
|
|
ts = runq_choose_from(&tdq->tdq_timeshare, tdq->tdq_ridx);
|
|
if (ts != NULL) {
|
|
KASSERT(ts->ts_thread->td_priority >= PRI_MIN_TIMESHARE,
|
|
("tdq_choose: Invalid priority on timeshare queue %d",
|
|
ts->ts_thread->td_priority));
|
|
return (ts);
|
|
}
|
|
|
|
ts = runq_choose(&tdq->tdq_idle);
|
|
if (ts != NULL) {
|
|
KASSERT(ts->ts_thread->td_priority >= PRI_MIN_IDLE,
|
|
("tdq_choose: Invalid priority on idle queue %d",
|
|
ts->ts_thread->td_priority));
|
|
return (ts);
|
|
}
|
|
|
|
return (NULL);
|
|
}
|
|
|
|
/*
|
|
* Initialize a thread queue.
|
|
*/
|
|
static void
|
|
tdq_setup(struct tdq *tdq)
|
|
{
|
|
|
|
snprintf(tdq->tdq_name, sizeof(tdq->tdq_name),
|
|
"sched lock %d", (int)TDQ_ID(tdq));
|
|
mtx_init(&tdq->tdq_lock, tdq->tdq_name, "sched lock",
|
|
MTX_SPIN | MTX_RECURSE);
|
|
runq_init(&tdq->tdq_realtime);
|
|
runq_init(&tdq->tdq_timeshare);
|
|
runq_init(&tdq->tdq_idle);
|
|
tdq->tdq_load = 0;
|
|
}
|
|
|
|
/*
|
|
* Setup the thread queues and initialize the topology based on MD
|
|
* information.
|
|
*/
|
|
static void
|
|
sched_setup(void *dummy)
|
|
{
|
|
struct tdq *tdq;
|
|
#ifdef SMP
|
|
int balance_groups;
|
|
int i;
|
|
|
|
balance_groups = 0;
|
|
/*
|
|
* Initialize the tdqs.
|
|
*/
|
|
for (i = 0; i < MAXCPU; i++) {
|
|
tdq = &tdq_cpu[i];
|
|
tdq_setup(&tdq_cpu[i]);
|
|
}
|
|
if (smp_topology == NULL) {
|
|
struct tdq_group *tdg;
|
|
int cpus;
|
|
|
|
for (cpus = 0, i = 0; i < MAXCPU; i++) {
|
|
if (CPU_ABSENT(i))
|
|
continue;
|
|
tdq = &tdq_cpu[i];
|
|
tdg = &tdq_groups[cpus];
|
|
/*
|
|
* Setup a tdq group with one member.
|
|
*/
|
|
tdq->tdq_transferable = 0;
|
|
tdq->tdq_group = tdg;
|
|
tdg->tdg_cpus = 1;
|
|
tdg->tdg_idlemask = 0;
|
|
tdg->tdg_cpumask = tdg->tdg_mask = 1 << i;
|
|
tdg->tdg_load = 0;
|
|
tdg->tdg_transferable = 0;
|
|
LIST_INIT(&tdg->tdg_members);
|
|
LIST_INSERT_HEAD(&tdg->tdg_members, tdq, tdq_siblings);
|
|
cpus++;
|
|
}
|
|
tdg_maxid = cpus - 1;
|
|
} else {
|
|
struct tdq_group *tdg;
|
|
struct cpu_group *cg;
|
|
int j;
|
|
|
|
topology = 1;
|
|
for (i = 0; i < smp_topology->ct_count; i++) {
|
|
cg = &smp_topology->ct_group[i];
|
|
tdg = &tdq_groups[i];
|
|
/*
|
|
* Initialize the group.
|
|
*/
|
|
tdg->tdg_idlemask = 0;
|
|
tdg->tdg_load = 0;
|
|
tdg->tdg_transferable = 0;
|
|
tdg->tdg_cpus = cg->cg_count;
|
|
tdg->tdg_cpumask = cg->cg_mask;
|
|
LIST_INIT(&tdg->tdg_members);
|
|
/*
|
|
* Find all of the group members and add them.
|
|
*/
|
|
for (j = 0; j < MAXCPU; j++) {
|
|
if ((cg->cg_mask & (1 << j)) != 0) {
|
|
if (tdg->tdg_mask == 0)
|
|
tdg->tdg_mask = 1 << j;
|
|
tdq_cpu[j].tdq_transferable = 0;
|
|
tdq_cpu[j].tdq_group = tdg;
|
|
LIST_INSERT_HEAD(&tdg->tdg_members,
|
|
&tdq_cpu[j], tdq_siblings);
|
|
}
|
|
}
|
|
if (tdg->tdg_cpus > 1)
|
|
balance_groups = 1;
|
|
}
|
|
tdg_maxid = smp_topology->ct_count - 1;
|
|
}
|
|
/*
|
|
* Initialize long-term cpu balancing algorithm.
|
|
*/
|
|
callout_init(&balco, CALLOUT_MPSAFE);
|
|
callout_init(&gbalco, CALLOUT_MPSAFE);
|
|
sched_balance(NULL);
|
|
if (balance_groups)
|
|
sched_balance_groups(NULL);
|
|
|
|
#else
|
|
tdq_setup(TDQ_SELF());
|
|
#endif
|
|
/*
|
|
* To avoid divide-by-zero, we set realstathz a dummy value
|
|
* in case which sched_clock() called before sched_initticks().
|
|
*/
|
|
realstathz = hz;
|
|
sched_slice = (realstathz/10); /* ~100ms */
|
|
tickincr = 1 << SCHED_TICK_SHIFT;
|
|
|
|
/* Add thread0's load since it's running. */
|
|
tdq = TDQ_SELF();
|
|
TDQ_LOCK(tdq);
|
|
tdq_load_add(tdq, &td_sched0);
|
|
TDQ_UNLOCK(tdq);
|
|
}
|
|
|
|
/*
|
|
* This routine determines the tickincr after stathz and hz are setup.
|
|
*/
|
|
/* ARGSUSED */
|
|
static void
|
|
sched_initticks(void *dummy)
|
|
{
|
|
int incr;
|
|
|
|
realstathz = stathz ? stathz : hz;
|
|
sched_slice = (realstathz/10); /* ~100ms */
|
|
|
|
/*
|
|
* tickincr is shifted out by 10 to avoid rounding errors due to
|
|
* hz not being evenly divisible by stathz on all platforms.
|
|
*/
|
|
incr = (hz << SCHED_TICK_SHIFT) / realstathz;
|
|
/*
|
|
* This does not work for values of stathz that are more than
|
|
* 1 << SCHED_TICK_SHIFT * hz. In practice this does not happen.
|
|
*/
|
|
if (incr == 0)
|
|
incr = 1;
|
|
tickincr = incr;
|
|
#ifdef SMP
|
|
affinity = SCHED_AFFINITY_DEFAULT;
|
|
#endif
|
|
}
|
|
|
|
|
|
/*
|
|
* This is the core of the interactivity algorithm. Determines a score based
|
|
* on past behavior. It is the ratio of sleep time to run time scaled to
|
|
* a [0, 100] integer. This is the voluntary sleep time of a process, which
|
|
* differs from the cpu usage because it does not account for time spent
|
|
* waiting on a run-queue. Would be prettier if we had floating point.
|
|
*/
|
|
static int
|
|
sched_interact_score(struct thread *td)
|
|
{
|
|
struct td_sched *ts;
|
|
int div;
|
|
|
|
ts = td->td_sched;
|
|
/*
|
|
* The score is only needed if this is likely to be an interactive
|
|
* task. Don't go through the expense of computing it if there's
|
|
* no chance.
|
|
*/
|
|
if (sched_interact <= SCHED_INTERACT_HALF &&
|
|
ts->ts_runtime >= ts->ts_slptime)
|
|
return (SCHED_INTERACT_HALF);
|
|
|
|
if (ts->ts_runtime > ts->ts_slptime) {
|
|
div = max(1, ts->ts_runtime / SCHED_INTERACT_HALF);
|
|
return (SCHED_INTERACT_HALF +
|
|
(SCHED_INTERACT_HALF - (ts->ts_slptime / div)));
|
|
}
|
|
if (ts->ts_slptime > ts->ts_runtime) {
|
|
div = max(1, ts->ts_slptime / SCHED_INTERACT_HALF);
|
|
return (ts->ts_runtime / div);
|
|
}
|
|
/* runtime == slptime */
|
|
if (ts->ts_runtime)
|
|
return (SCHED_INTERACT_HALF);
|
|
|
|
/*
|
|
* This can happen if slptime and runtime are 0.
|
|
*/
|
|
return (0);
|
|
|
|
}
|
|
|
|
/*
|
|
* Scale the scheduling priority according to the "interactivity" of this
|
|
* process.
|
|
*/
|
|
static void
|
|
sched_priority(struct thread *td)
|
|
{
|
|
int score;
|
|
int pri;
|
|
|
|
if (td->td_pri_class != PRI_TIMESHARE)
|
|
return;
|
|
/*
|
|
* If the score is interactive we place the thread in the realtime
|
|
* queue with a priority that is less than kernel and interrupt
|
|
* priorities. These threads are not subject to nice restrictions.
|
|
*
|
|
* Scores greater than this are placed on the normal timeshare queue
|
|
* where the priority is partially decided by the most recent cpu
|
|
* utilization and the rest is decided by nice value.
|
|
*/
|
|
score = sched_interact_score(td);
|
|
if (score < sched_interact) {
|
|
pri = PRI_MIN_REALTIME;
|
|
pri += ((PRI_MAX_REALTIME - PRI_MIN_REALTIME) / sched_interact)
|
|
* score;
|
|
KASSERT(pri >= PRI_MIN_REALTIME && pri <= PRI_MAX_REALTIME,
|
|
("sched_priority: invalid interactive priority %d score %d",
|
|
pri, score));
|
|
} else {
|
|
pri = SCHED_PRI_MIN;
|
|
if (td->td_sched->ts_ticks)
|
|
pri += SCHED_PRI_TICKS(td->td_sched);
|
|
pri += SCHED_PRI_NICE(td->td_proc->p_nice);
|
|
KASSERT(pri >= PRI_MIN_TIMESHARE && pri <= PRI_MAX_TIMESHARE,
|
|
("sched_priority: invalid priority %d: nice %d, "
|
|
"ticks %d ftick %d ltick %d tick pri %d",
|
|
pri, td->td_proc->p_nice, td->td_sched->ts_ticks,
|
|
td->td_sched->ts_ftick, td->td_sched->ts_ltick,
|
|
SCHED_PRI_TICKS(td->td_sched)));
|
|
}
|
|
sched_user_prio(td, pri);
|
|
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* This routine enforces a maximum limit on the amount of scheduling history
|
|
* kept. It is called after either the slptime or runtime is adjusted. This
|
|
* function is ugly due to integer math.
|
|
*/
|
|
static void
|
|
sched_interact_update(struct thread *td)
|
|
{
|
|
struct td_sched *ts;
|
|
u_int sum;
|
|
|
|
ts = td->td_sched;
|
|
sum = ts->ts_runtime + ts->ts_slptime;
|
|
if (sum < SCHED_SLP_RUN_MAX)
|
|
return;
|
|
/*
|
|
* This only happens from two places:
|
|
* 1) We have added an unusual amount of run time from fork_exit.
|
|
* 2) We have added an unusual amount of sleep time from sched_sleep().
|
|
*/
|
|
if (sum > SCHED_SLP_RUN_MAX * 2) {
|
|
if (ts->ts_runtime > ts->ts_slptime) {
|
|
ts->ts_runtime = SCHED_SLP_RUN_MAX;
|
|
ts->ts_slptime = 1;
|
|
} else {
|
|
ts->ts_slptime = SCHED_SLP_RUN_MAX;
|
|
ts->ts_runtime = 1;
|
|
}
|
|
return;
|
|
}
|
|
/*
|
|
* If we have exceeded by more than 1/5th then the algorithm below
|
|
* will not bring us back into range. Dividing by two here forces
|
|
* us into the range of [4/5 * SCHED_INTERACT_MAX, SCHED_INTERACT_MAX]
|
|
*/
|
|
if (sum > (SCHED_SLP_RUN_MAX / 5) * 6) {
|
|
ts->ts_runtime /= 2;
|
|
ts->ts_slptime /= 2;
|
|
return;
|
|
}
|
|
ts->ts_runtime = (ts->ts_runtime / 5) * 4;
|
|
ts->ts_slptime = (ts->ts_slptime / 5) * 4;
|
|
}
|
|
|
|
/*
|
|
* Scale back the interactivity history when a child thread is created. The
|
|
* history is inherited from the parent but the thread may behave totally
|
|
* differently. For example, a shell spawning a compiler process. We want
|
|
* to learn that the compiler is behaving badly very quickly.
|
|
*/
|
|
static void
|
|
sched_interact_fork(struct thread *td)
|
|
{
|
|
int ratio;
|
|
int sum;
|
|
|
|
sum = td->td_sched->ts_runtime + td->td_sched->ts_slptime;
|
|
if (sum > SCHED_SLP_RUN_FORK) {
|
|
ratio = sum / SCHED_SLP_RUN_FORK;
|
|
td->td_sched->ts_runtime /= ratio;
|
|
td->td_sched->ts_slptime /= ratio;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Called from proc0_init() to setup the scheduler fields.
|
|
*/
|
|
void
|
|
schedinit(void)
|
|
{
|
|
|
|
/*
|
|
* Set up the scheduler specific parts of proc0.
|
|
*/
|
|
proc0.p_sched = NULL; /* XXX */
|
|
thread0.td_sched = &td_sched0;
|
|
thread0.td_lock = TDQ_LOCKPTR(TDQ_SELF());
|
|
td_sched0.ts_ltick = ticks;
|
|
td_sched0.ts_ftick = ticks;
|
|
td_sched0.ts_thread = &thread0;
|
|
}
|
|
|
|
/*
|
|
* This is only somewhat accurate since given many processes of the same
|
|
* priority they will switch when their slices run out, which will be
|
|
* at most sched_slice stathz ticks.
|
|
*/
|
|
int
|
|
sched_rr_interval(void)
|
|
{
|
|
|
|
/* Convert sched_slice to hz */
|
|
return (hz/(realstathz/sched_slice));
|
|
}
|
|
|
|
/*
|
|
* Update the percent cpu tracking information when it is requested or
|
|
* the total history exceeds the maximum. We keep a sliding history of
|
|
* tick counts that slowly decays. This is less precise than the 4BSD
|
|
* mechanism since it happens with less regular and frequent events.
|
|
*/
|
|
static void
|
|
sched_pctcpu_update(struct td_sched *ts)
|
|
{
|
|
|
|
if (ts->ts_ticks == 0)
|
|
return;
|
|
if (ticks - (hz / 10) < ts->ts_ltick &&
|
|
SCHED_TICK_TOTAL(ts) < SCHED_TICK_MAX)
|
|
return;
|
|
/*
|
|
* Adjust counters and watermark for pctcpu calc.
|
|
*/
|
|
if (ts->ts_ltick > ticks - SCHED_TICK_TARG)
|
|
ts->ts_ticks = (ts->ts_ticks / (ticks - ts->ts_ftick)) *
|
|
SCHED_TICK_TARG;
|
|
else
|
|
ts->ts_ticks = 0;
|
|
ts->ts_ltick = ticks;
|
|
ts->ts_ftick = ts->ts_ltick - SCHED_TICK_TARG;
|
|
}
|
|
|
|
/*
|
|
* Adjust the priority of a thread. Move it to the appropriate run-queue
|
|
* if necessary. This is the back-end for several priority related
|
|
* functions.
|
|
*/
|
|
static void
|
|
sched_thread_priority(struct thread *td, u_char prio)
|
|
{
|
|
struct td_sched *ts;
|
|
|
|
CTR6(KTR_SCHED, "sched_prio: %p(%s) prio %d newprio %d by %p(%s)",
|
|
td, td->td_proc->p_comm, td->td_priority, prio, curthread,
|
|
curthread->td_proc->p_comm);
|
|
ts = td->td_sched;
|
|
THREAD_LOCK_ASSERT(td, MA_OWNED);
|
|
if (td->td_priority == prio)
|
|
return;
|
|
|
|
if (TD_ON_RUNQ(td) && prio < td->td_priority) {
|
|
/*
|
|
* If the priority has been elevated due to priority
|
|
* propagation, we may have to move ourselves to a new
|
|
* queue. This could be optimized to not re-add in some
|
|
* cases.
|
|
*/
|
|
sched_rem(td);
|
|
td->td_priority = prio;
|
|
sched_add(td, SRQ_BORROWING);
|
|
} else {
|
|
#ifdef SMP
|
|
struct tdq *tdq;
|
|
|
|
tdq = TDQ_CPU(ts->ts_cpu);
|
|
if (prio < tdq->tdq_lowpri)
|
|
tdq->tdq_lowpri = prio;
|
|
#endif
|
|
td->td_priority = prio;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Update a thread's priority when it is lent another thread's
|
|
* priority.
|
|
*/
|
|
void
|
|
sched_lend_prio(struct thread *td, u_char prio)
|
|
{
|
|
|
|
td->td_flags |= TDF_BORROWING;
|
|
sched_thread_priority(td, prio);
|
|
}
|
|
|
|
/*
|
|
* Restore a thread's priority when priority propagation is
|
|
* over. The prio argument is the minimum priority the thread
|
|
* needs to have to satisfy other possible priority lending
|
|
* requests. If the thread's regular priority is less
|
|
* important than prio, the thread will keep a priority boost
|
|
* of prio.
|
|
*/
|
|
void
|
|
sched_unlend_prio(struct thread *td, u_char prio)
|
|
{
|
|
u_char base_pri;
|
|
|
|
if (td->td_base_pri >= PRI_MIN_TIMESHARE &&
|
|
td->td_base_pri <= PRI_MAX_TIMESHARE)
|
|
base_pri = td->td_user_pri;
|
|
else
|
|
base_pri = td->td_base_pri;
|
|
if (prio >= base_pri) {
|
|
td->td_flags &= ~TDF_BORROWING;
|
|
sched_thread_priority(td, base_pri);
|
|
} else
|
|
sched_lend_prio(td, prio);
|
|
}
|
|
|
|
/*
|
|
* Standard entry for setting the priority to an absolute value.
|
|
*/
|
|
void
|
|
sched_prio(struct thread *td, u_char prio)
|
|
{
|
|
u_char oldprio;
|
|
|
|
/* First, update the base priority. */
|
|
td->td_base_pri = prio;
|
|
|
|
/*
|
|
* If the thread is borrowing another thread's priority, don't
|
|
* ever lower the priority.
|
|
*/
|
|
if (td->td_flags & TDF_BORROWING && td->td_priority < prio)
|
|
return;
|
|
|
|
/* Change the real priority. */
|
|
oldprio = td->td_priority;
|
|
sched_thread_priority(td, prio);
|
|
|
|
/*
|
|
* If the thread is on a turnstile, then let the turnstile update
|
|
* its state.
|
|
*/
|
|
if (TD_ON_LOCK(td) && oldprio != prio)
|
|
turnstile_adjust(td, oldprio);
|
|
}
|
|
|
|
/*
|
|
* Set the base user priority, does not effect current running priority.
|
|
*/
|
|
void
|
|
sched_user_prio(struct thread *td, u_char prio)
|
|
{
|
|
u_char oldprio;
|
|
|
|
td->td_base_user_pri = prio;
|
|
if (td->td_flags & TDF_UBORROWING && td->td_user_pri <= prio)
|
|
return;
|
|
oldprio = td->td_user_pri;
|
|
td->td_user_pri = prio;
|
|
|
|
if (TD_ON_UPILOCK(td) && oldprio != prio)
|
|
umtx_pi_adjust(td, oldprio);
|
|
}
|
|
|
|
void
|
|
sched_lend_user_prio(struct thread *td, u_char prio)
|
|
{
|
|
u_char oldprio;
|
|
|
|
td->td_flags |= TDF_UBORROWING;
|
|
|
|
oldprio = td->td_user_pri;
|
|
td->td_user_pri = prio;
|
|
|
|
if (TD_ON_UPILOCK(td) && oldprio != prio)
|
|
umtx_pi_adjust(td, oldprio);
|
|
}
|
|
|
|
void
|
|
sched_unlend_user_prio(struct thread *td, u_char prio)
|
|
{
|
|
u_char base_pri;
|
|
|
|
base_pri = td->td_base_user_pri;
|
|
if (prio >= base_pri) {
|
|
td->td_flags &= ~TDF_UBORROWING;
|
|
sched_user_prio(td, base_pri);
|
|
} else
|
|
sched_lend_user_prio(td, prio);
|
|
}
|
|
|
|
/*
|
|
* Add the thread passed as 'newtd' to the run queue before selecting
|
|
* the next thread to run. This is only used for KSE.
|
|
*/
|
|
static void
|
|
sched_switchin(struct tdq *tdq, struct thread *td)
|
|
{
|
|
#ifdef SMP
|
|
spinlock_enter();
|
|
TDQ_UNLOCK(tdq);
|
|
thread_lock(td);
|
|
spinlock_exit();
|
|
sched_setcpu(td->td_sched, TDQ_ID(tdq), SRQ_YIELDING);
|
|
#else
|
|
td->td_lock = TDQ_LOCKPTR(tdq);
|
|
#endif
|
|
tdq_add(tdq, td, SRQ_YIELDING);
|
|
MPASS(td->td_lock == TDQ_LOCKPTR(tdq));
|
|
}
|
|
|
|
/*
|
|
* Block a thread for switching. Similar to thread_block() but does not
|
|
* bump the spin count.
|
|
*/
|
|
static inline struct mtx *
|
|
thread_block_switch(struct thread *td)
|
|
{
|
|
struct mtx *lock;
|
|
|
|
THREAD_LOCK_ASSERT(td, MA_OWNED);
|
|
lock = td->td_lock;
|
|
td->td_lock = &blocked_lock;
|
|
mtx_unlock_spin(lock);
|
|
|
|
return (lock);
|
|
}
|
|
|
|
/*
|
|
* Release a thread that was blocked with thread_block_switch().
|
|
*/
|
|
static inline void
|
|
thread_unblock_switch(struct thread *td, struct mtx *mtx)
|
|
{
|
|
atomic_store_rel_ptr((volatile uintptr_t *)&td->td_lock,
|
|
(uintptr_t)mtx);
|
|
}
|
|
|
|
/*
|
|
* Switch threads. This function has to handle threads coming in while
|
|
* blocked for some reason, running, or idle. It also must deal with
|
|
* migrating a thread from one queue to another as running threads may
|
|
* be assigned elsewhere via binding.
|
|
*/
|
|
void
|
|
sched_switch(struct thread *td, struct thread *newtd, int flags)
|
|
{
|
|
struct tdq *tdq;
|
|
struct td_sched *ts;
|
|
struct mtx *mtx;
|
|
int cpuid;
|
|
|
|
THREAD_LOCK_ASSERT(td, MA_OWNED);
|
|
|
|
cpuid = PCPU_GET(cpuid);
|
|
tdq = TDQ_CPU(cpuid);
|
|
ts = td->td_sched;
|
|
mtx = TDQ_LOCKPTR(tdq);
|
|
#ifdef SMP
|
|
ts->ts_rltick = ticks;
|
|
if (newtd && newtd->td_priority < tdq->tdq_lowpri)
|
|
tdq->tdq_lowpri = newtd->td_priority;
|
|
#endif
|
|
td->td_lastcpu = td->td_oncpu;
|
|
td->td_oncpu = NOCPU;
|
|
td->td_flags &= ~TDF_NEEDRESCHED;
|
|
td->td_owepreempt = 0;
|
|
/*
|
|
* The lock pointer in an idle thread should never change. Reset it
|
|
* to CAN_RUN as well.
|
|
*/
|
|
if (TD_IS_IDLETHREAD(td)) {
|
|
MPASS(td->td_lock == TDQ_LOCKPTR(tdq));
|
|
TD_SET_CAN_RUN(td);
|
|
} else if (TD_IS_RUNNING(td)) {
|
|
MPASS(td->td_lock == TDQ_LOCKPTR(tdq));
|
|
/* Remove our load so the selection algorithm is not biased. */
|
|
tdq_load_rem(tdq, ts);
|
|
sched_add(td, (flags & SW_PREEMPT) ?
|
|
SRQ_OURSELF|SRQ_YIELDING|SRQ_PREEMPTED :
|
|
SRQ_OURSELF|SRQ_YIELDING);
|
|
/*
|
|
* When migrating we return from sched_add with an extra
|
|
* spinlock nesting, the tdq locked, and a blocked thread.
|
|
* This is to optimize out an extra block/unblock cycle here.
|
|
*/
|
|
if (ts->ts_cpu != cpuid) {
|
|
mtx = TDQ_LOCKPTR(TDQ_CPU(ts->ts_cpu));
|
|
mtx_unlock_spin(mtx);
|
|
TDQ_LOCK(tdq);
|
|
spinlock_exit();
|
|
}
|
|
} else {
|
|
/* This thread must be going to sleep. */
|
|
TDQ_LOCK(tdq);
|
|
mtx = thread_block_switch(td);
|
|
tdq_load_rem(tdq, ts);
|
|
}
|
|
/*
|
|
* We enter here with the thread blocked and assigned to the
|
|
* appropriate cpu run-queue or sleep-queue and with the current
|
|
* thread-queue locked.
|
|
*/
|
|
TDQ_LOCK_ASSERT(tdq, MA_OWNED | MA_NOTRECURSED);
|
|
/*
|
|
* If KSE assigned a new thread just add it here and let choosethread
|
|
* select the best one.
|
|
*/
|
|
if (newtd != NULL)
|
|
sched_switchin(tdq, newtd);
|
|
newtd = choosethread();
|
|
/*
|
|
* Call the MD code to switch contexts if necessary.
|
|
*/
|
|
if (td != newtd) {
|
|
#ifdef HWPMC_HOOKS
|
|
if (PMC_PROC_IS_USING_PMCS(td->td_proc))
|
|
PMC_SWITCH_CONTEXT(td, PMC_FN_CSW_OUT);
|
|
#endif
|
|
cpu_switch(td, newtd, mtx);
|
|
/*
|
|
* We may return from cpu_switch on a different cpu. However,
|
|
* we always return with td_lock pointing to the current cpu's
|
|
* run queue lock.
|
|
*/
|
|
cpuid = PCPU_GET(cpuid);
|
|
tdq = TDQ_CPU(cpuid);
|
|
TDQ_LOCKPTR(tdq)->mtx_lock = (uintptr_t)td;
|
|
#ifdef HWPMC_HOOKS
|
|
if (PMC_PROC_IS_USING_PMCS(td->td_proc))
|
|
PMC_SWITCH_CONTEXT(td, PMC_FN_CSW_IN);
|
|
#endif
|
|
} else
|
|
thread_unblock_switch(td, mtx);
|
|
/*
|
|
* Assert that all went well and return.
|
|
*/
|
|
#ifdef SMP
|
|
/* We should always get here with the lowest priority td possible */
|
|
tdq->tdq_lowpri = td->td_priority;
|
|
#endif
|
|
TDQ_LOCK_ASSERT(tdq, MA_OWNED|MA_NOTRECURSED);
|
|
MPASS(td->td_lock == TDQ_LOCKPTR(tdq));
|
|
td->td_oncpu = cpuid;
|
|
}
|
|
|
|
/*
|
|
* Adjust thread priorities as a result of a nice request.
|
|
*/
|
|
void
|
|
sched_nice(struct proc *p, int nice)
|
|
{
|
|
struct thread *td;
|
|
|
|
PROC_LOCK_ASSERT(p, MA_OWNED);
|
|
PROC_SLOCK_ASSERT(p, MA_OWNED);
|
|
|
|
p->p_nice = nice;
|
|
FOREACH_THREAD_IN_PROC(p, td) {
|
|
thread_lock(td);
|
|
sched_priority(td);
|
|
sched_prio(td, td->td_base_user_pri);
|
|
thread_unlock(td);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Record the sleep time for the interactivity scorer.
|
|
*/
|
|
void
|
|
sched_sleep(struct thread *td)
|
|
{
|
|
|
|
THREAD_LOCK_ASSERT(td, MA_OWNED);
|
|
|
|
td->td_sched->ts_slptick = ticks;
|
|
}
|
|
|
|
/*
|
|
* Schedule a thread to resume execution and record how long it voluntarily
|
|
* slept. We also update the pctcpu, interactivity, and priority.
|
|
*/
|
|
void
|
|
sched_wakeup(struct thread *td)
|
|
{
|
|
struct td_sched *ts;
|
|
int slptick;
|
|
|
|
THREAD_LOCK_ASSERT(td, MA_OWNED);
|
|
ts = td->td_sched;
|
|
/*
|
|
* If we slept for more than a tick update our interactivity and
|
|
* priority.
|
|
*/
|
|
slptick = ts->ts_slptick;
|
|
ts->ts_slptick = 0;
|
|
if (slptick && slptick != ticks) {
|
|
u_int hzticks;
|
|
|
|
hzticks = (ticks - slptick) << SCHED_TICK_SHIFT;
|
|
ts->ts_slptime += hzticks;
|
|
sched_interact_update(td);
|
|
sched_pctcpu_update(ts);
|
|
sched_priority(td);
|
|
}
|
|
/* Reset the slice value after we sleep. */
|
|
ts->ts_slice = sched_slice;
|
|
sched_add(td, SRQ_BORING);
|
|
}
|
|
|
|
/*
|
|
* Penalize the parent for creating a new child and initialize the child's
|
|
* priority.
|
|
*/
|
|
void
|
|
sched_fork(struct thread *td, struct thread *child)
|
|
{
|
|
THREAD_LOCK_ASSERT(td, MA_OWNED);
|
|
sched_fork_thread(td, child);
|
|
/*
|
|
* Penalize the parent and child for forking.
|
|
*/
|
|
sched_interact_fork(child);
|
|
sched_priority(child);
|
|
td->td_sched->ts_runtime += tickincr;
|
|
sched_interact_update(td);
|
|
sched_priority(td);
|
|
}
|
|
|
|
/*
|
|
* Fork a new thread, may be within the same process.
|
|
*/
|
|
void
|
|
sched_fork_thread(struct thread *td, struct thread *child)
|
|
{
|
|
struct td_sched *ts;
|
|
struct td_sched *ts2;
|
|
|
|
/*
|
|
* Initialize child.
|
|
*/
|
|
THREAD_LOCK_ASSERT(td, MA_OWNED);
|
|
sched_newthread(child);
|
|
child->td_lock = TDQ_LOCKPTR(TDQ_SELF());
|
|
ts = td->td_sched;
|
|
ts2 = child->td_sched;
|
|
ts2->ts_cpu = ts->ts_cpu;
|
|
ts2->ts_runq = NULL;
|
|
/*
|
|
* Grab our parents cpu estimation information and priority.
|
|
*/
|
|
ts2->ts_ticks = ts->ts_ticks;
|
|
ts2->ts_ltick = ts->ts_ltick;
|
|
ts2->ts_ftick = ts->ts_ftick;
|
|
child->td_user_pri = td->td_user_pri;
|
|
child->td_base_user_pri = td->td_base_user_pri;
|
|
/*
|
|
* And update interactivity score.
|
|
*/
|
|
ts2->ts_slptime = ts->ts_slptime;
|
|
ts2->ts_runtime = ts->ts_runtime;
|
|
ts2->ts_slice = 1; /* Attempt to quickly learn interactivity. */
|
|
}
|
|
|
|
/*
|
|
* Adjust the priority class of a thread.
|
|
*/
|
|
void
|
|
sched_class(struct thread *td, int class)
|
|
{
|
|
|
|
THREAD_LOCK_ASSERT(td, MA_OWNED);
|
|
if (td->td_pri_class == class)
|
|
return;
|
|
|
|
#ifdef SMP
|
|
/*
|
|
* On SMP if we're on the RUNQ we must adjust the transferable
|
|
* count because could be changing to or from an interrupt
|
|
* class.
|
|
*/
|
|
if (TD_ON_RUNQ(td)) {
|
|
struct tdq *tdq;
|
|
|
|
tdq = TDQ_CPU(td->td_sched->ts_cpu);
|
|
if (THREAD_CAN_MIGRATE(td)) {
|
|
tdq->tdq_transferable--;
|
|
tdq->tdq_group->tdg_transferable--;
|
|
}
|
|
td->td_pri_class = class;
|
|
if (THREAD_CAN_MIGRATE(td)) {
|
|
tdq->tdq_transferable++;
|
|
tdq->tdq_group->tdg_transferable++;
|
|
}
|
|
}
|
|
#endif
|
|
td->td_pri_class = class;
|
|
}
|
|
|
|
/*
|
|
* Return some of the child's priority and interactivity to the parent.
|
|
*/
|
|
void
|
|
sched_exit(struct proc *p, struct thread *child)
|
|
{
|
|
struct thread *td;
|
|
|
|
CTR3(KTR_SCHED, "sched_exit: %p(%s) prio %d",
|
|
child, child->td_proc->p_comm, child->td_priority);
|
|
|
|
PROC_SLOCK_ASSERT(p, MA_OWNED);
|
|
td = FIRST_THREAD_IN_PROC(p);
|
|
sched_exit_thread(td, child);
|
|
}
|
|
|
|
/*
|
|
* Penalize another thread for the time spent on this one. This helps to
|
|
* worsen the priority and interactivity of processes which schedule batch
|
|
* jobs such as make. This has little effect on the make process itself but
|
|
* causes new processes spawned by it to receive worse scores immediately.
|
|
*/
|
|
void
|
|
sched_exit_thread(struct thread *td, struct thread *child)
|
|
{
|
|
|
|
CTR3(KTR_SCHED, "sched_exit_thread: %p(%s) prio %d",
|
|
child, child->td_proc->p_comm, child->td_priority);
|
|
|
|
#ifdef KSE
|
|
/*
|
|
* KSE forks and exits so often that this penalty causes short-lived
|
|
* threads to always be non-interactive. This causes mozilla to
|
|
* crawl under load.
|
|
*/
|
|
if ((td->td_pflags & TDP_SA) && td->td_proc == child->td_proc)
|
|
return;
|
|
#endif
|
|
/*
|
|
* Give the child's runtime to the parent without returning the
|
|
* sleep time as a penalty to the parent. This causes shells that
|
|
* launch expensive things to mark their children as expensive.
|
|
*/
|
|
thread_lock(td);
|
|
td->td_sched->ts_runtime += child->td_sched->ts_runtime;
|
|
sched_interact_update(td);
|
|
sched_priority(td);
|
|
thread_unlock(td);
|
|
}
|
|
|
|
/*
|
|
* Fix priorities on return to user-space. Priorities may be elevated due
|
|
* to static priorities in msleep() or similar.
|
|
*/
|
|
void
|
|
sched_userret(struct thread *td)
|
|
{
|
|
/*
|
|
* XXX we cheat slightly on the locking here to avoid locking in
|
|
* the usual case. Setting td_priority here is essentially an
|
|
* incomplete workaround for not setting it properly elsewhere.
|
|
* Now that some interrupt handlers are threads, not setting it
|
|
* properly elsewhere can clobber it in the window between setting
|
|
* it here and returning to user mode, so don't waste time setting
|
|
* it perfectly here.
|
|
*/
|
|
KASSERT((td->td_flags & TDF_BORROWING) == 0,
|
|
("thread with borrowed priority returning to userland"));
|
|
if (td->td_priority != td->td_user_pri) {
|
|
thread_lock(td);
|
|
td->td_priority = td->td_user_pri;
|
|
td->td_base_pri = td->td_user_pri;
|
|
thread_unlock(td);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Handle a stathz tick. This is really only relevant for timeshare
|
|
* threads.
|
|
*/
|
|
void
|
|
sched_clock(struct thread *td)
|
|
{
|
|
struct tdq *tdq;
|
|
struct td_sched *ts;
|
|
|
|
THREAD_LOCK_ASSERT(td, MA_OWNED);
|
|
tdq = TDQ_SELF();
|
|
/*
|
|
* Advance the insert index once for each tick to ensure that all
|
|
* threads get a chance to run.
|
|
*/
|
|
if (tdq->tdq_idx == tdq->tdq_ridx) {
|
|
tdq->tdq_idx = (tdq->tdq_idx + 1) % RQ_NQS;
|
|
if (TAILQ_EMPTY(&tdq->tdq_timeshare.rq_queues[tdq->tdq_ridx]))
|
|
tdq->tdq_ridx = tdq->tdq_idx;
|
|
}
|
|
ts = td->td_sched;
|
|
/*
|
|
* We only do slicing code for TIMESHARE threads.
|
|
*/
|
|
if (td->td_pri_class != PRI_TIMESHARE)
|
|
return;
|
|
/*
|
|
* We used a tick; charge it to the thread so that we can compute our
|
|
* interactivity.
|
|
*/
|
|
td->td_sched->ts_runtime += tickincr;
|
|
sched_interact_update(td);
|
|
/*
|
|
* We used up one time slice.
|
|
*/
|
|
if (--ts->ts_slice > 0)
|
|
return;
|
|
/*
|
|
* We're out of time, recompute priorities and requeue.
|
|
*/
|
|
sched_priority(td);
|
|
td->td_flags |= TDF_NEEDRESCHED;
|
|
}
|
|
|
|
/*
|
|
* Called once per hz tick. Used for cpu utilization information. This
|
|
* is easier than trying to scale based on stathz.
|
|
*/
|
|
void
|
|
sched_tick(void)
|
|
{
|
|
struct td_sched *ts;
|
|
|
|
ts = curthread->td_sched;
|
|
/* Adjust ticks for pctcpu */
|
|
ts->ts_ticks += 1 << SCHED_TICK_SHIFT;
|
|
ts->ts_ltick = ticks;
|
|
/*
|
|
* Update if we've exceeded our desired tick threshhold by over one
|
|
* second.
|
|
*/
|
|
if (ts->ts_ftick + SCHED_TICK_MAX < ts->ts_ltick)
|
|
sched_pctcpu_update(ts);
|
|
}
|
|
|
|
/*
|
|
* Return whether the current CPU has runnable tasks. Used for in-kernel
|
|
* cooperative idle threads.
|
|
*/
|
|
int
|
|
sched_runnable(void)
|
|
{
|
|
struct tdq *tdq;
|
|
int load;
|
|
|
|
load = 1;
|
|
|
|
tdq = TDQ_SELF();
|
|
if ((curthread->td_flags & TDF_IDLETD) != 0) {
|
|
if (tdq->tdq_load > 0)
|
|
goto out;
|
|
} else
|
|
if (tdq->tdq_load - 1 > 0)
|
|
goto out;
|
|
load = 0;
|
|
out:
|
|
return (load);
|
|
}
|
|
|
|
/*
|
|
* Choose the highest priority thread to run. The thread is removed from
|
|
* the run-queue while running however the load remains. For SMP we set
|
|
* the tdq in the global idle bitmask if it idles here.
|
|
*/
|
|
struct thread *
|
|
sched_choose(void)
|
|
{
|
|
#ifdef SMP
|
|
struct tdq_group *tdg;
|
|
#endif
|
|
struct td_sched *ts;
|
|
struct tdq *tdq;
|
|
|
|
tdq = TDQ_SELF();
|
|
TDQ_LOCK_ASSERT(tdq, MA_OWNED);
|
|
ts = tdq_choose(tdq);
|
|
if (ts) {
|
|
tdq_runq_rem(tdq, ts);
|
|
return (ts->ts_thread);
|
|
}
|
|
#ifdef SMP
|
|
/*
|
|
* We only set the idled bit when all of the cpus in the group are
|
|
* idle. Otherwise we could get into a situation where a thread bounces
|
|
* back and forth between two idle cores on seperate physical CPUs.
|
|
*/
|
|
tdg = tdq->tdq_group;
|
|
tdg->tdg_idlemask |= PCPU_GET(cpumask);
|
|
if (tdg->tdg_idlemask == tdg->tdg_cpumask)
|
|
atomic_set_int(&tdq_idle, tdg->tdg_mask);
|
|
tdq->tdq_lowpri = PRI_MAX_IDLE;
|
|
#endif
|
|
return (PCPU_GET(idlethread));
|
|
}
|
|
|
|
/*
|
|
* Set owepreempt if necessary. Preemption never happens directly in ULE,
|
|
* we always request it once we exit a critical section.
|
|
*/
|
|
static inline void
|
|
sched_setpreempt(struct thread *td)
|
|
{
|
|
struct thread *ctd;
|
|
int cpri;
|
|
int pri;
|
|
|
|
ctd = curthread;
|
|
pri = td->td_priority;
|
|
cpri = ctd->td_priority;
|
|
if (td->td_priority < ctd->td_priority)
|
|
curthread->td_flags |= TDF_NEEDRESCHED;
|
|
if (panicstr != NULL || pri >= cpri || cold || TD_IS_INHIBITED(ctd))
|
|
return;
|
|
/*
|
|
* Always preempt IDLE threads. Otherwise only if the preempting
|
|
* thread is an ithread.
|
|
*/
|
|
if (pri > preempt_thresh && cpri < PRI_MIN_IDLE)
|
|
return;
|
|
ctd->td_owepreempt = 1;
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* Add a thread to a thread queue. Initializes priority, slice, runq, and
|
|
* add it to the appropriate queue. This is the internal function called
|
|
* when the tdq is predetermined.
|
|
*/
|
|
void
|
|
tdq_add(struct tdq *tdq, struct thread *td, int flags)
|
|
{
|
|
struct td_sched *ts;
|
|
int class;
|
|
#ifdef SMP
|
|
int cpumask;
|
|
#endif
|
|
|
|
TDQ_LOCK_ASSERT(tdq, MA_OWNED);
|
|
KASSERT((td->td_inhibitors == 0),
|
|
("sched_add: trying to run inhibited thread"));
|
|
KASSERT((TD_CAN_RUN(td) || TD_IS_RUNNING(td)),
|
|
("sched_add: bad thread state"));
|
|
KASSERT(td->td_proc->p_sflag & PS_INMEM,
|
|
("sched_add: process swapped out"));
|
|
|
|
ts = td->td_sched;
|
|
class = PRI_BASE(td->td_pri_class);
|
|
TD_SET_RUNQ(td);
|
|
if (ts->ts_slice == 0)
|
|
ts->ts_slice = sched_slice;
|
|
/*
|
|
* Pick the run queue based on priority.
|
|
*/
|
|
if (td->td_priority <= PRI_MAX_REALTIME)
|
|
ts->ts_runq = &tdq->tdq_realtime;
|
|
else if (td->td_priority <= PRI_MAX_TIMESHARE)
|
|
ts->ts_runq = &tdq->tdq_timeshare;
|
|
else
|
|
ts->ts_runq = &tdq->tdq_idle;
|
|
#ifdef SMP
|
|
cpumask = 1 << ts->ts_cpu;
|
|
/*
|
|
* If we had been idle, clear our bit in the group and potentially
|
|
* the global bitmap.
|
|
*/
|
|
if ((class != PRI_IDLE && class != PRI_ITHD) &&
|
|
(tdq->tdq_group->tdg_idlemask & cpumask) != 0) {
|
|
/*
|
|
* Check to see if our group is unidling, and if so, remove it
|
|
* from the global idle mask.
|
|
*/
|
|
if (tdq->tdq_group->tdg_idlemask ==
|
|
tdq->tdq_group->tdg_cpumask)
|
|
atomic_clear_int(&tdq_idle, tdq->tdq_group->tdg_mask);
|
|
/*
|
|
* Now remove ourselves from the group specific idle mask.
|
|
*/
|
|
tdq->tdq_group->tdg_idlemask &= ~cpumask;
|
|
}
|
|
if (td->td_priority < tdq->tdq_lowpri)
|
|
tdq->tdq_lowpri = td->td_priority;
|
|
#endif
|
|
tdq_runq_add(tdq, ts, flags);
|
|
tdq_load_add(tdq, ts);
|
|
}
|
|
|
|
/*
|
|
* Select the target thread queue and add a thread to it. Request
|
|
* preemption or IPI a remote processor if required.
|
|
*/
|
|
void
|
|
sched_add(struct thread *td, int flags)
|
|
{
|
|
struct td_sched *ts;
|
|
struct tdq *tdq;
|
|
#ifdef SMP
|
|
int cpuid;
|
|
int cpu;
|
|
#endif
|
|
CTR5(KTR_SCHED, "sched_add: %p(%s) prio %d by %p(%s)",
|
|
td, td->td_proc->p_comm, td->td_priority, curthread,
|
|
curthread->td_proc->p_comm);
|
|
THREAD_LOCK_ASSERT(td, MA_OWNED);
|
|
ts = td->td_sched;
|
|
/*
|
|
* Recalculate the priority before we select the target cpu or
|
|
* run-queue.
|
|
*/
|
|
if (PRI_BASE(td->td_pri_class) == PRI_TIMESHARE)
|
|
sched_priority(td);
|
|
#ifdef SMP
|
|
cpuid = PCPU_GET(cpuid);
|
|
/*
|
|
* Pick the destination cpu and if it isn't ours transfer to the
|
|
* target cpu.
|
|
*/
|
|
if (td->td_priority <= PRI_MAX_ITHD && THREAD_CAN_MIGRATE(td))
|
|
cpu = cpuid;
|
|
else if (!THREAD_CAN_MIGRATE(td))
|
|
cpu = ts->ts_cpu;
|
|
else
|
|
cpu = sched_pickcpu(ts, flags);
|
|
tdq = sched_setcpu(ts, cpu, flags);
|
|
tdq_add(tdq, td, flags);
|
|
if (cpu != cpuid) {
|
|
tdq_notify(ts);
|
|
return;
|
|
}
|
|
#else
|
|
tdq = TDQ_SELF();
|
|
TDQ_LOCK(tdq);
|
|
/*
|
|
* Now that the thread is moving to the run-queue, set the lock
|
|
* to the scheduler's lock.
|
|
*/
|
|
thread_lock_set(td, TDQ_LOCKPTR(tdq));
|
|
tdq_add(tdq, td, flags);
|
|
#endif
|
|
if (!(flags & SRQ_YIELDING))
|
|
sched_setpreempt(td);
|
|
}
|
|
|
|
/*
|
|
* Remove a thread from a run-queue without running it. This is used
|
|
* when we're stealing a thread from a remote queue. Otherwise all threads
|
|
* exit by calling sched_exit_thread() and sched_throw() themselves.
|
|
*/
|
|
void
|
|
sched_rem(struct thread *td)
|
|
{
|
|
struct tdq *tdq;
|
|
struct td_sched *ts;
|
|
|
|
CTR5(KTR_SCHED, "sched_rem: %p(%s) prio %d by %p(%s)",
|
|
td, td->td_proc->p_comm, td->td_priority, curthread,
|
|
curthread->td_proc->p_comm);
|
|
ts = td->td_sched;
|
|
tdq = TDQ_CPU(ts->ts_cpu);
|
|
TDQ_LOCK_ASSERT(tdq, MA_OWNED);
|
|
MPASS(td->td_lock == TDQ_LOCKPTR(tdq));
|
|
KASSERT(TD_ON_RUNQ(td),
|
|
("sched_rem: thread not on run queue"));
|
|
tdq_runq_rem(tdq, ts);
|
|
tdq_load_rem(tdq, ts);
|
|
TD_SET_CAN_RUN(td);
|
|
}
|
|
|
|
/*
|
|
* Fetch cpu utilization information. Updates on demand.
|
|
*/
|
|
fixpt_t
|
|
sched_pctcpu(struct thread *td)
|
|
{
|
|
fixpt_t pctcpu;
|
|
struct td_sched *ts;
|
|
|
|
pctcpu = 0;
|
|
ts = td->td_sched;
|
|
if (ts == NULL)
|
|
return (0);
|
|
|
|
thread_lock(td);
|
|
if (ts->ts_ticks) {
|
|
int rtick;
|
|
|
|
sched_pctcpu_update(ts);
|
|
/* How many rtick per second ? */
|
|
rtick = min(SCHED_TICK_HZ(ts) / SCHED_TICK_SECS, hz);
|
|
pctcpu = (FSCALE * ((FSCALE * rtick)/hz)) >> FSHIFT;
|
|
}
|
|
td->td_proc->p_swtime = ts->ts_ltick - ts->ts_ftick;
|
|
thread_unlock(td);
|
|
|
|
return (pctcpu);
|
|
}
|
|
|
|
/*
|
|
* Bind a thread to a target cpu.
|
|
*/
|
|
void
|
|
sched_bind(struct thread *td, int cpu)
|
|
{
|
|
struct td_sched *ts;
|
|
|
|
THREAD_LOCK_ASSERT(td, MA_OWNED);
|
|
ts = td->td_sched;
|
|
if (ts->ts_flags & TSF_BOUND)
|
|
sched_unbind(td);
|
|
ts->ts_flags |= TSF_BOUND;
|
|
#ifdef SMP
|
|
sched_pin();
|
|
if (PCPU_GET(cpuid) == cpu)
|
|
return;
|
|
ts->ts_cpu = cpu;
|
|
/* When we return from mi_switch we'll be on the correct cpu. */
|
|
mi_switch(SW_VOL, NULL);
|
|
#endif
|
|
}
|
|
|
|
/*
|
|
* Release a bound thread.
|
|
*/
|
|
void
|
|
sched_unbind(struct thread *td)
|
|
{
|
|
struct td_sched *ts;
|
|
|
|
THREAD_LOCK_ASSERT(td, MA_OWNED);
|
|
ts = td->td_sched;
|
|
if ((ts->ts_flags & TSF_BOUND) == 0)
|
|
return;
|
|
ts->ts_flags &= ~TSF_BOUND;
|
|
#ifdef SMP
|
|
sched_unpin();
|
|
#endif
|
|
}
|
|
|
|
int
|
|
sched_is_bound(struct thread *td)
|
|
{
|
|
THREAD_LOCK_ASSERT(td, MA_OWNED);
|
|
return (td->td_sched->ts_flags & TSF_BOUND);
|
|
}
|
|
|
|
/*
|
|
* Basic yield call.
|
|
*/
|
|
void
|
|
sched_relinquish(struct thread *td)
|
|
{
|
|
thread_lock(td);
|
|
if (td->td_pri_class == PRI_TIMESHARE)
|
|
sched_prio(td, PRI_MAX_TIMESHARE);
|
|
SCHED_STAT_INC(switch_relinquish);
|
|
mi_switch(SW_VOL, NULL);
|
|
thread_unlock(td);
|
|
}
|
|
|
|
/*
|
|
* Return the total system load.
|
|
*/
|
|
int
|
|
sched_load(void)
|
|
{
|
|
#ifdef SMP
|
|
int total;
|
|
int i;
|
|
|
|
total = 0;
|
|
for (i = 0; i <= tdg_maxid; i++)
|
|
total += TDQ_GROUP(i)->tdg_load;
|
|
return (total);
|
|
#else
|
|
return (TDQ_SELF()->tdq_sysload);
|
|
#endif
|
|
}
|
|
|
|
int
|
|
sched_sizeof_proc(void)
|
|
{
|
|
return (sizeof(struct proc));
|
|
}
|
|
|
|
int
|
|
sched_sizeof_thread(void)
|
|
{
|
|
return (sizeof(struct thread) + sizeof(struct td_sched));
|
|
}
|
|
|
|
/*
|
|
* The actual idle process.
|
|
*/
|
|
void
|
|
sched_idletd(void *dummy)
|
|
{
|
|
struct thread *td;
|
|
struct tdq *tdq;
|
|
|
|
td = curthread;
|
|
tdq = TDQ_SELF();
|
|
mtx_assert(&Giant, MA_NOTOWNED);
|
|
/* ULE relies on preemption for idle interruption. */
|
|
for (;;) {
|
|
#ifdef SMP
|
|
if (tdq_idled(tdq))
|
|
cpu_idle();
|
|
#else
|
|
cpu_idle();
|
|
#endif
|
|
}
|
|
}
|
|
|
|
/*
|
|
* A CPU is entering for the first time or a thread is exiting.
|
|
*/
|
|
void
|
|
sched_throw(struct thread *td)
|
|
{
|
|
struct tdq *tdq;
|
|
|
|
tdq = TDQ_SELF();
|
|
if (td == NULL) {
|
|
/* Correct spinlock nesting and acquire the correct lock. */
|
|
TDQ_LOCK(tdq);
|
|
spinlock_exit();
|
|
} else {
|
|
MPASS(td->td_lock == TDQ_LOCKPTR(tdq));
|
|
tdq_load_rem(tdq, td->td_sched);
|
|
}
|
|
KASSERT(curthread->td_md.md_spinlock_count == 1, ("invalid count"));
|
|
PCPU_SET(switchtime, cpu_ticks());
|
|
PCPU_SET(switchticks, ticks);
|
|
cpu_throw(td, choosethread()); /* doesn't return */
|
|
}
|
|
|
|
/*
|
|
* This is called from fork_exit(). Just acquire the correct locks and
|
|
* let fork do the rest of the work.
|
|
*/
|
|
void
|
|
sched_fork_exit(struct thread *td)
|
|
{
|
|
struct td_sched *ts;
|
|
struct tdq *tdq;
|
|
int cpuid;
|
|
|
|
/*
|
|
* Finish setting up thread glue so that it begins execution in a
|
|
* non-nested critical section with the scheduler lock held.
|
|
*/
|
|
cpuid = PCPU_GET(cpuid);
|
|
tdq = TDQ_CPU(cpuid);
|
|
ts = td->td_sched;
|
|
if (TD_IS_IDLETHREAD(td))
|
|
td->td_lock = TDQ_LOCKPTR(tdq);
|
|
MPASS(td->td_lock == TDQ_LOCKPTR(tdq));
|
|
td->td_oncpu = cpuid;
|
|
TDQ_LOCKPTR(tdq)->mtx_lock = (uintptr_t)td;
|
|
THREAD_LOCK_ASSERT(td, MA_OWNED | MA_NOTRECURSED);
|
|
}
|
|
|
|
static SYSCTL_NODE(_kern, OID_AUTO, sched, CTLFLAG_RW, 0,
|
|
"Scheduler");
|
|
SYSCTL_STRING(_kern_sched, OID_AUTO, name, CTLFLAG_RD, "ULE", 0,
|
|
"Scheduler name");
|
|
SYSCTL_INT(_kern_sched, OID_AUTO, slice, CTLFLAG_RW, &sched_slice, 0,
|
|
"Slice size for timeshare threads");
|
|
SYSCTL_INT(_kern_sched, OID_AUTO, interact, CTLFLAG_RW, &sched_interact, 0,
|
|
"Interactivity score threshold");
|
|
SYSCTL_INT(_kern_sched, OID_AUTO, preempt_thresh, CTLFLAG_RW, &preempt_thresh,
|
|
0,"Min priority for preemption, lower priorities have greater precedence");
|
|
#ifdef SMP
|
|
SYSCTL_INT(_kern_sched, OID_AUTO, pick_pri, CTLFLAG_RW, &pick_pri, 0,
|
|
"Pick the target cpu based on priority rather than load.");
|
|
SYSCTL_INT(_kern_sched, OID_AUTO, affinity, CTLFLAG_RW, &affinity, 0,
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"Number of hz ticks to keep thread affinity for");
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SYSCTL_INT(_kern_sched, OID_AUTO, tryself, CTLFLAG_RW, &tryself, 0, "");
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SYSCTL_INT(_kern_sched, OID_AUTO, balance, CTLFLAG_RW, &rebalance, 0,
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"Enables the long-term load balancer");
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SYSCTL_INT(_kern_sched, OID_AUTO, balance_secs, CTLFLAG_RW, &balance_secs, 0,
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|
"Average frequence in seconds to run the long-term balancer");
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SYSCTL_INT(_kern_sched, OID_AUTO, steal_htt, CTLFLAG_RW, &steal_htt, 0,
|
|
"Steals work from another hyper-threaded core on idle");
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|
SYSCTL_INT(_kern_sched, OID_AUTO, steal_idle, CTLFLAG_RW, &steal_idle, 0,
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|
"Attempts to steal work from other cores before idling");
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|
SYSCTL_INT(_kern_sched, OID_AUTO, steal_thresh, CTLFLAG_RW, &steal_thresh, 0,
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|
"Minimum load on remote cpu before we'll steal");
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|
SYSCTL_INT(_kern_sched, OID_AUTO, topology, CTLFLAG_RD, &topology, 0,
|
|
"True when a topology has been specified by the MD code.");
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|
#endif
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/* ps compat */
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static fixpt_t ccpu = 0.95122942450071400909 * FSCALE; /* exp(-1/20) */
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SYSCTL_INT(_kern, OID_AUTO, ccpu, CTLFLAG_RD, &ccpu, 0, "");
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|
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#define KERN_SWITCH_INCLUDE 1
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#include "kern/kern_switch.c"
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