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freebsd-skq/sys/kern/sched_ule.c

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/*-
* Copyright (c) 2002-2005, Jeffrey Roberson <jeff@freebsd.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice unmodified, this list of conditions, and the following
* disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_hwpmc_hooks.h"
#include "opt_sched.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kdb.h>
#include <sys/kernel.h>
#include <sys/ktr.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/resource.h>
#include <sys/resourcevar.h>
#include <sys/sched.h>
#include <sys/smp.h>
#include <sys/sx.h>
#include <sys/sysctl.h>
#include <sys/sysproto.h>
#include <sys/turnstile.h>
#include <sys/umtx.h>
#include <sys/vmmeter.h>
#ifdef KTRACE
#include <sys/uio.h>
#include <sys/ktrace.h>
#endif
#ifdef HWPMC_HOOKS
#include <sys/pmckern.h>
#endif
#include <machine/cpu.h>
#include <machine/smp.h>
/* decay 95% of `p_pctcpu' in 60 seconds; see CCPU_SHIFT before changing */
/* XXX This is bogus compatability crap for ps */
static fixpt_t ccpu = 0.95122942450071400909 * FSCALE; /* exp(-1/20) */
SYSCTL_INT(_kern, OID_AUTO, ccpu, CTLFLAG_RD, &ccpu, 0, "");
static void sched_setup(void *dummy);
SYSINIT(sched_setup, SI_SUB_RUN_QUEUE, SI_ORDER_FIRST, sched_setup, NULL)
static void sched_initticks(void *dummy);
SYSINIT(sched_initticks, SI_SUB_CLOCKS, SI_ORDER_THIRD, sched_initticks, NULL)
static SYSCTL_NODE(_kern, OID_AUTO, sched, CTLFLAG_RW, 0, "Scheduler");
SYSCTL_STRING(_kern_sched, OID_AUTO, name, CTLFLAG_RD, "ule", 0,
"Scheduler name");
static int slice_min = 1;
SYSCTL_INT(_kern_sched, OID_AUTO, slice_min, CTLFLAG_RW, &slice_min, 0, "");
static int slice_max = 10;
SYSCTL_INT(_kern_sched, OID_AUTO, slice_max, CTLFLAG_RW, &slice_max, 0, "");
int realstathz;
int tickincr = 1 << 10;
/*
* The following datastructures are allocated within their parent structure
* but are scheduler specific.
*/
/*
* Thread scheduler specific section.
* fields int he thread structure that are specific to this scheduler.
*/
struct td_sched {
TAILQ_ENTRY(td_sched) ts_procq; /* (j/z) Run queue. */
int ts_flags; /* (j) TSF_* flags. */
struct thread *ts_thread; /* (*) Active associated thread. */
fixpt_t ts_pctcpu; /* (j) %cpu during p_swtime. */
u_char ts_rqindex; /* (j) Run queue index. */
enum {
TSS_THREAD = 0x0, /* slaved to thread state */
TSS_ONRUNQ
} ts_state; /* (j) thread sched specific status. */
int ts_slptime;
int ts_slice;
struct runq *ts_runq;
u_char ts_cpu; /* CPU that we have affinity for. */
/* The following variables are only used for pctcpu calculation */
int ts_ltick; /* Last tick that we were running on */
int ts_ftick; /* First tick that we were running on */
int ts_ticks; /* Tick count */
/* originally from kg_sched */
int skg_slptime; /* Number of ticks we vol. slept */
int skg_runtime; /* Number of ticks we were running */
};
#define ts_assign ts_procq.tqe_next
/* flags kept in ts_flags */
#define TSF_ASSIGNED 0x0001 /* Thread is being migrated. */
#define TSF_BOUND 0x0002 /* Thread can not migrate. */
#define TSF_XFERABLE 0x0004 /* Thread was added as transferable. */
#define TSF_HOLD 0x0008 /* Thread is temporarily bound. */
#define TSF_REMOVED 0x0010 /* Thread was removed while ASSIGNED */
#define TSF_INTERNAL 0x0020 /* Thread added due to migration. */
#define TSF_PREEMPTED 0x0040 /* Thread was preempted */
#define TSF_DIDRUN 0x02000 /* Thread actually ran. */
#define TSF_EXIT 0x04000 /* Thread is being killed. */
static struct td_sched td_sched0;
/*
* The priority is primarily determined by the interactivity score. Thus, we
* give lower(better) priorities to kse groups that use less CPU. The nice
* value is then directly added to this to allow nice to have some effect
* on latency.
*
* PRI_RANGE: Total priority range for timeshare threads.
* PRI_NRESV: Number of nice values.
* PRI_BASE: The start of the dynamic range.
*/
#define SCHED_PRI_RANGE (PRI_MAX_TIMESHARE - PRI_MIN_TIMESHARE + 1)
#define SCHED_PRI_NRESV ((PRIO_MAX - PRIO_MIN) + 1)
#define SCHED_PRI_NHALF (SCHED_PRI_NRESV / 2)
#define SCHED_PRI_BASE (PRI_MIN_TIMESHARE)
#define SCHED_PRI_INTERACT(score) \
((score) * SCHED_PRI_RANGE / SCHED_INTERACT_MAX)
/*
* These determine the interactivity of a process.
*
* SLP_RUN_MAX: Maximum amount of sleep time + run time we'll accumulate
* before throttling back.
* SLP_RUN_FORK: Maximum slp+run time to inherit at fork time.
* INTERACT_MAX: Maximum interactivity value. Smaller is better.
* INTERACT_THRESH: Threshhold for placement on the current runq.
*/
#define SCHED_SLP_RUN_MAX ((hz * 5) << 10)
#define SCHED_SLP_RUN_FORK ((hz / 2) << 10)
#define SCHED_INTERACT_MAX (100)
#define SCHED_INTERACT_HALF (SCHED_INTERACT_MAX / 2)
#define SCHED_INTERACT_THRESH (30)
/*
* These parameters and macros determine the size of the time slice that is
* granted to each thread.
*
* SLICE_MIN: Minimum time slice granted, in units of ticks.
* SLICE_MAX: Maximum time slice granted.
* SLICE_RANGE: Range of available time slices scaled by hz.
* SLICE_SCALE: The number slices granted per val in the range of [0, max].
* SLICE_NICE: Determine the amount of slice granted to a scaled nice.
* SLICE_NTHRESH: The nice cutoff point for slice assignment.
*/
#define SCHED_SLICE_MIN (slice_min)
#define SCHED_SLICE_MAX (slice_max)
#define SCHED_SLICE_INTERACTIVE (slice_max)
#define SCHED_SLICE_NTHRESH (SCHED_PRI_NHALF - 1)
#define SCHED_SLICE_RANGE (SCHED_SLICE_MAX - SCHED_SLICE_MIN + 1)
#define SCHED_SLICE_SCALE(val, max) (((val) * SCHED_SLICE_RANGE) / (max))
#define SCHED_SLICE_NICE(nice) \
(SCHED_SLICE_MAX - SCHED_SLICE_SCALE((nice), SCHED_SLICE_NTHRESH))
/*
* This macro determines whether or not the thread belongs on the current or
* next run queue.
*/
#define SCHED_INTERACTIVE(td) \
(sched_interact_score(td) < SCHED_INTERACT_THRESH)
#define SCHED_CURR(td, ts) \
((ts->ts_thread->td_flags & TDF_BORROWING) || \
(ts->ts_flags & TSF_PREEMPTED) || SCHED_INTERACTIVE(td))
/*
* Cpu percentage computation macros and defines.
*
* SCHED_CPU_TIME: Number of seconds to average the cpu usage across.
* SCHED_CPU_TICKS: Number of hz ticks to average the cpu usage across.
*/
#define SCHED_CPU_TIME 10
#define SCHED_CPU_TICKS (hz * SCHED_CPU_TIME)
/*
* tdq - per processor runqs and statistics.
*/
struct tdq {
struct runq ksq_idle; /* Queue of IDLE threads. */
struct runq ksq_timeshare[2]; /* Run queues for !IDLE. */
struct runq *ksq_next; /* Next timeshare queue. */
struct runq *ksq_curr; /* Current queue. */
int ksq_load_timeshare; /* Load for timeshare. */
int ksq_load; /* Aggregate load. */
short ksq_nice[SCHED_PRI_NRESV]; /* threadss in each nice bin. */
short ksq_nicemin; /* Least nice. */
#ifdef SMP
int ksq_transferable;
LIST_ENTRY(tdq) ksq_siblings; /* Next in tdq group. */
struct tdq_group *ksq_group; /* Our processor group. */
volatile struct td_sched *ksq_assigned; /* assigned by another CPU. */
#else
int ksq_sysload; /* For loadavg, !ITHD load. */
#endif
};
#ifdef SMP
/*
* tdq groups are groups of processors which can cheaply share threads. When
* one processor in the group goes idle it will check the runqs of the other
* processors in its group prior to halting and waiting for an interrupt.
* These groups are suitable for SMT (Symetric Multi-Threading) and not NUMA.
* In a numa environment we'd want an idle bitmap per group and a two tiered
* load balancer.
*/
struct tdq_group {
int ksg_cpus; /* Count of CPUs in this tdq group. */
cpumask_t ksg_cpumask; /* Mask of cpus in this group. */
cpumask_t ksg_idlemask; /* Idle cpus in this group. */
cpumask_t ksg_mask; /* Bit mask for first cpu. */
int ksg_load; /* Total load of this group. */
int ksg_transferable; /* Transferable load of this group. */
LIST_HEAD(, tdq) ksg_members; /* Linked list of all members. */
};
#endif
/*
* One kse queue per processor.
*/
#ifdef SMP
static cpumask_t tdq_idle;
static int ksg_maxid;
static struct tdq tdq_cpu[MAXCPU];
static struct tdq_group tdq_groups[MAXCPU];
static int bal_tick;
static int gbal_tick;
static int balance_groups;
#define TDQ_SELF() (&tdq_cpu[PCPU_GET(cpuid)])
#define TDQ_CPU(x) (&tdq_cpu[(x)])
#define TDQ_ID(x) ((x) - tdq_cpu)
#define TDQ_GROUP(x) (&tdq_groups[(x)])
#else /* !SMP */
static struct tdq tdq_cpu;
#define TDQ_SELF() (&tdq_cpu)
#define TDQ_CPU(x) (&tdq_cpu)
#endif
static struct td_sched *sched_choose(void); /* XXX Should be thread * */
static void sched_slice(struct td_sched *);
static void sched_priority(struct thread *);
static void sched_thread_priority(struct thread *, u_char);
static int sched_interact_score(struct thread *);
static void sched_interact_update(struct thread *);
static void sched_interact_fork(struct thread *);
static void sched_pctcpu_update(struct td_sched *);
/* Operations on per processor queues */
static struct td_sched * tdq_choose(struct tdq *);
static void tdq_setup(struct tdq *);
static void tdq_load_add(struct tdq *, struct td_sched *);
static void tdq_load_rem(struct tdq *, struct td_sched *);
static __inline void tdq_runq_add(struct tdq *, struct td_sched *, int);
static __inline void tdq_runq_rem(struct tdq *, struct td_sched *);
static void tdq_nice_add(struct tdq *, int);
static void tdq_nice_rem(struct tdq *, int);
void tdq_print(int cpu);
#ifdef SMP
static int tdq_transfer(struct tdq *, struct td_sched *, int);
static struct td_sched *runq_steal(struct runq *);
static void sched_balance(void);
static void sched_balance_groups(void);
static void sched_balance_group(struct tdq_group *);
static void sched_balance_pair(struct tdq *, struct tdq *);
static void tdq_move(struct tdq *, int);
static int tdq_idled(struct tdq *);
static void tdq_notify(struct td_sched *, int);
static void tdq_assign(struct tdq *);
static struct td_sched *tdq_steal(struct tdq *, int);
#define THREAD_CAN_MIGRATE(ts) \
((ts)->ts_thread->td_pinned == 0 && ((ts)->ts_flags & TSF_BOUND) == 0)
#endif
void
tdq_print(int cpu)
{
struct tdq *tdq;
int i;
tdq = TDQ_CPU(cpu);
printf("tdq:\n");
printf("\tload: %d\n", tdq->ksq_load);
printf("\tload TIMESHARE: %d\n", tdq->ksq_load_timeshare);
#ifdef SMP
printf("\tload transferable: %d\n", tdq->ksq_transferable);
#endif
printf("\tnicemin:\t%d\n", tdq->ksq_nicemin);
printf("\tnice counts:\n");
for (i = 0; i < SCHED_PRI_NRESV; i++)
if (tdq->ksq_nice[i])
printf("\t\t%d = %d\n",
i - SCHED_PRI_NHALF, tdq->ksq_nice[i]);
}
static __inline void
tdq_runq_add(struct tdq *tdq, struct td_sched *ts, int flags)
{
#ifdef SMP
if (THREAD_CAN_MIGRATE(ts)) {
tdq->ksq_transferable++;
tdq->ksq_group->ksg_transferable++;
ts->ts_flags |= TSF_XFERABLE;
}
#endif
if (ts->ts_flags & TSF_PREEMPTED)
flags |= SRQ_PREEMPTED;
runq_add(ts->ts_runq, ts, flags);
}
static __inline void
tdq_runq_rem(struct tdq *tdq, struct td_sched *ts)
{
#ifdef SMP
if (ts->ts_flags & TSF_XFERABLE) {
tdq->ksq_transferable--;
tdq->ksq_group->ksg_transferable--;
ts->ts_flags &= ~TSF_XFERABLE;
}
#endif
runq_remove(ts->ts_runq, ts);
}
static void
tdq_load_add(struct tdq *tdq, struct td_sched *ts)
{
int class;
mtx_assert(&sched_lock, MA_OWNED);
class = PRI_BASE(ts->ts_thread->td_pri_class);
if (class == PRI_TIMESHARE)
tdq->ksq_load_timeshare++;
tdq->ksq_load++;
CTR1(KTR_SCHED, "load: %d", tdq->ksq_load);
if (class != PRI_ITHD && (ts->ts_thread->td_proc->p_flag & P_NOLOAD) == 0)
#ifdef SMP
tdq->ksq_group->ksg_load++;
#else
tdq->ksq_sysload++;
#endif
if (ts->ts_thread->td_pri_class == PRI_TIMESHARE)
tdq_nice_add(tdq, ts->ts_thread->td_proc->p_nice);
}
static void
tdq_load_rem(struct tdq *tdq, struct td_sched *ts)
{
int class;
mtx_assert(&sched_lock, MA_OWNED);
class = PRI_BASE(ts->ts_thread->td_pri_class);
if (class == PRI_TIMESHARE)
tdq->ksq_load_timeshare--;
if (class != PRI_ITHD && (ts->ts_thread->td_proc->p_flag & P_NOLOAD) == 0)
#ifdef SMP
tdq->ksq_group->ksg_load--;
#else
tdq->ksq_sysload--;
#endif
tdq->ksq_load--;
CTR1(KTR_SCHED, "load: %d", tdq->ksq_load);
ts->ts_runq = NULL;
if (ts->ts_thread->td_pri_class == PRI_TIMESHARE)
tdq_nice_rem(tdq, ts->ts_thread->td_proc->p_nice);
}
static void
tdq_nice_add(struct tdq *tdq, int nice)
{
mtx_assert(&sched_lock, MA_OWNED);
/* Normalize to zero. */
tdq->ksq_nice[nice + SCHED_PRI_NHALF]++;
if (nice < tdq->ksq_nicemin || tdq->ksq_load_timeshare == 1)
tdq->ksq_nicemin = nice;
}
static void
tdq_nice_rem(struct tdq *tdq, int nice)
{
int n;
mtx_assert(&sched_lock, MA_OWNED);
/* Normalize to zero. */
n = nice + SCHED_PRI_NHALF;
tdq->ksq_nice[n]--;
KASSERT(tdq->ksq_nice[n] >= 0, ("Negative nice count."));
/*
* If this wasn't the smallest nice value or there are more in
* this bucket we can just return. Otherwise we have to recalculate
* the smallest nice.
*/
if (nice != tdq->ksq_nicemin ||
tdq->ksq_nice[n] != 0 ||
tdq->ksq_load_timeshare == 0)
return;
for (; n < SCHED_PRI_NRESV; n++)
if (tdq->ksq_nice[n]) {
tdq->ksq_nicemin = n - SCHED_PRI_NHALF;
return;
}
}
#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
* algorithm simplicity and more gradual effects on load in larger systems.
*
* It could be improved by considering the priorities and slices assigned to
* each task prior to balancing them. There are many pathological cases with
* any approach and so the semi random algorithm below may work as well as any.
*
*/
static void
sched_balance(void)
{
struct tdq_group *high;
struct tdq_group *low;
struct tdq_group *ksg;
int cnt;
int i;
bal_tick = ticks + (random() % (hz * 2));
if (smp_started == 0)
return;
low = high = NULL;
i = random() % (ksg_maxid + 1);
for (cnt = 0; cnt <= ksg_maxid; cnt++) {
ksg = TDQ_GROUP(i);
/*
* Find the CPU with the highest load that has some
* threads to transfer.
*/
if ((high == NULL || ksg->ksg_load > high->ksg_load)
&& ksg->ksg_transferable)
high = ksg;
if (low == NULL || ksg->ksg_load < low->ksg_load)
low = ksg;
if (++i > ksg_maxid)
i = 0;
}
if (low != NULL && high != NULL && high != low)
sched_balance_pair(LIST_FIRST(&high->ksg_members),
LIST_FIRST(&low->ksg_members));
}
static void
sched_balance_groups(void)
{
int i;
gbal_tick = ticks + (random() % (hz * 2));
mtx_assert(&sched_lock, MA_OWNED);
if (smp_started)
for (i = 0; i <= ksg_maxid; i++)
sched_balance_group(TDQ_GROUP(i));
}
static void
sched_balance_group(struct tdq_group *ksg)
{
struct tdq *tdq;
struct tdq *high;
struct tdq *low;
int load;
if (ksg->ksg_transferable == 0)
return;
low = NULL;
high = NULL;
LIST_FOREACH(tdq, &ksg->ksg_members, ksq_siblings) {
load = tdq->ksq_load;
if (high == NULL || load > high->ksq_load)
high = tdq;
if (low == NULL || load < low->ksq_load)
low = tdq;
}
if (high != NULL && low != NULL && high != low)
sched_balance_pair(high, low);
}
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;
/*
* 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->ksq_group == low->ksq_group) {
transferable = high->ksq_transferable;
high_load = high->ksq_load;
low_load = low->ksq_load;
} else {
transferable = high->ksq_group->ksg_transferable;
high_load = high->ksq_group->ksg_load;
low_load = low->ksq_group->ksg_load;
}
if (transferable == 0)
return;
/*
* Determine what the imbalance is and then adjust that to how many
* kses we actually have to give up (transferable).
*/
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, TDQ_ID(low));
return;
}
static void
tdq_move(struct tdq *from, int cpu)
{
struct tdq *tdq;
struct tdq *to;
struct td_sched *ts;
tdq = from;
to = TDQ_CPU(cpu);
ts = tdq_steal(tdq, 1);
if (ts == NULL) {
struct tdq_group *ksg;
ksg = tdq->ksq_group;
LIST_FOREACH(tdq, &ksg->ksg_members, ksq_siblings) {
if (tdq == from || tdq->ksq_transferable == 0)
continue;
ts = tdq_steal(tdq, 1);
break;
}
if (ts == NULL)
panic("tdq_move: No threads available with a "
"transferable count of %d\n",
ksg->ksg_transferable);
}
if (tdq == to)
return;
ts->ts_state = TSS_THREAD;
tdq_runq_rem(tdq, ts);
tdq_load_rem(tdq, ts);
tdq_notify(ts, cpu);
}
static int
tdq_idled(struct tdq *tdq)
{
struct tdq_group *ksg;
struct tdq *steal;
struct td_sched *ts;
ksg = tdq->ksq_group;
/*
* If we're in a cpu group, try and steal kses from another cpu in
* the group before idling.
*/
if (ksg->ksg_cpus > 1 && ksg->ksg_transferable) {
LIST_FOREACH(steal, &ksg->ksg_members, ksq_siblings) {
if (steal == tdq || steal->ksq_transferable == 0)
continue;
ts = tdq_steal(steal, 0);
if (ts == NULL)
continue;
ts->ts_state = TSS_THREAD;
tdq_runq_rem(steal, ts);
tdq_load_rem(steal, ts);
ts->ts_cpu = PCPU_GET(cpuid);
ts->ts_flags |= TSF_INTERNAL | TSF_HOLD;
sched_add(ts->ts_thread, SRQ_YIELDING);
return (0);
}
}
/*
* 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.
*/
ksg->ksg_idlemask |= PCPU_GET(cpumask);
if (ksg->ksg_idlemask != ksg->ksg_cpumask)
return (1);
atomic_set_int(&tdq_idle, ksg->ksg_mask);
return (1);
}
static void
tdq_assign(struct tdq *tdq)
{
struct td_sched *nts;
struct td_sched *ts;
do {
*(volatile struct td_sched **)&ts = tdq->ksq_assigned;
} while(!atomic_cmpset_ptr((volatile uintptr_t *)&tdq->ksq_assigned,
(uintptr_t)ts, (uintptr_t)NULL));
for (; ts != NULL; ts = nts) {
nts = ts->ts_assign;
tdq->ksq_group->ksg_load--;
tdq->ksq_load--;
ts->ts_flags &= ~TSF_ASSIGNED;
if (ts->ts_flags & TSF_REMOVED) {
ts->ts_flags &= ~TSF_REMOVED;
continue;
}
ts->ts_flags |= TSF_INTERNAL | TSF_HOLD;
sched_add(ts->ts_thread, SRQ_YIELDING);
}
}
static void
tdq_notify(struct td_sched *ts, int cpu)
{
struct tdq *tdq;
struct thread *td;
struct pcpu *pcpu;
int class;
int prio;
tdq = TDQ_CPU(cpu);
/* XXX */
class = PRI_BASE(ts->ts_thread->td_pri_class);
if ((class == PRI_TIMESHARE || class == PRI_REALTIME) &&
(tdq_idle & tdq->ksq_group->ksg_mask))
atomic_clear_int(&tdq_idle, tdq->ksq_group->ksg_mask);
tdq->ksq_group->ksg_load++;
tdq->ksq_load++;
ts->ts_cpu = cpu;
ts->ts_flags |= TSF_ASSIGNED;
prio = ts->ts_thread->td_priority;
/*
* Place a thread on another cpu's queue and force a resched.
*/
do {
*(volatile struct td_sched **)&ts->ts_assign = tdq->ksq_assigned;
} while(!atomic_cmpset_ptr((volatile uintptr_t *)&tdq->ksq_assigned,
(uintptr_t)ts->ts_assign, (uintptr_t)ts));
/*
* Without sched_lock we could lose a race where we set NEEDRESCHED
* on a thread that is switched out before the IPI is delivered. This
* would lead us to miss the resched. This will be a problem once
* sched_lock is pushed down.
*/
pcpu = pcpu_find(cpu);
td = pcpu->pc_curthread;
if (ts->ts_thread->td_priority < td->td_priority ||
td == pcpu->pc_idlethread) {
td->td_flags |= TDF_NEEDRESCHED;
ipi_selected(1 << cpu, IPI_AST);
}
}
static struct td_sched *
runq_steal(struct runq *rq)
{
struct rqhead *rqh;
struct rqbits *rqb;
struct td_sched *ts;
int word;
int bit;
mtx_assert(&sched_lock, MA_OWNED);
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))
return (ts);
}
}
}
return (NULL);
}
static struct td_sched *
tdq_steal(struct tdq *tdq, int stealidle)
{
struct td_sched *ts;
/*
* Steal from next first to try to get a non-interactive task that
* may not have run for a while.
*/
if ((ts = runq_steal(tdq->ksq_next)) != NULL)
return (ts);
if ((ts = runq_steal(tdq->ksq_curr)) != NULL)
return (ts);
if (stealidle)
return (runq_steal(&tdq->ksq_idle));
return (NULL);
}
int
tdq_transfer(struct tdq *tdq, struct td_sched *ts, int class)
{
struct tdq_group *nksg;
struct tdq_group *ksg;
struct tdq *old;
int cpu;
int idx;
if (smp_started == 0)
return (0);
cpu = 0;
/*
* If our load exceeds a certain threshold we should attempt to
* reassign this thread. The first candidate is the cpu that
* originally ran the thread. If it is idle, assign it there,
* otherwise, pick an idle cpu.
*
* The threshold at which we start to reassign kses has a large impact
* on the overall performance of the system. Tuned too high and
* some CPUs may idle. Too low and there will be excess migration
* and context switches.
*/
old = TDQ_CPU(ts->ts_cpu);
nksg = old->ksq_group;
ksg = tdq->ksq_group;
if (tdq_idle) {
if (tdq_idle & nksg->ksg_mask) {
cpu = ffs(nksg->ksg_idlemask);
if (cpu) {
CTR2(KTR_SCHED,
"tdq_transfer: %p found old cpu %X "
"in idlemask.", ts, cpu);
goto migrate;
}
}
/*
* Multiple cpus could find this bit simultaneously
* but the race shouldn't be terrible.
*/
cpu = ffs(tdq_idle);
if (cpu) {
CTR2(KTR_SCHED, "tdq_transfer: %p found %X "
"in idlemask.", ts, cpu);
goto migrate;
}
}
idx = 0;
#if 0
if (old->ksq_load < tdq->ksq_load) {
cpu = ts->ts_cpu + 1;
CTR2(KTR_SCHED, "tdq_transfer: %p old cpu %X "
"load less than ours.", ts, cpu);
goto migrate;
}
/*
* No new CPU was found, look for one with less load.
*/
for (idx = 0; idx <= ksg_maxid; idx++) {
nksg = TDQ_GROUP(idx);
if (nksg->ksg_load /*+ (nksg->ksg_cpus * 2)*/ < ksg->ksg_load) {
cpu = ffs(nksg->ksg_cpumask);
CTR2(KTR_SCHED, "tdq_transfer: %p cpu %X load less "
"than ours.", ts, cpu);
goto migrate;
}
}
#endif
/*
* If another cpu in this group has idled, assign a thread over
* to them after checking to see if there are idled groups.
*/
if (ksg->ksg_idlemask) {
cpu = ffs(ksg->ksg_idlemask);
if (cpu) {
CTR2(KTR_SCHED, "tdq_transfer: %p cpu %X idle in "
"group.", ts, cpu);
goto migrate;
}
}
return (0);
migrate:
/*
* Now that we've found an idle CPU, migrate the thread.
*/
cpu--;
ts->ts_runq = NULL;
tdq_notify(ts, cpu);
return (1);
}
#endif /* SMP */
/*
* Pick the highest priority task we have and return it.
*/
static struct td_sched *
tdq_choose(struct tdq *tdq)
{
struct runq *swap;
struct td_sched *ts;
int nice;
mtx_assert(&sched_lock, MA_OWNED);
swap = NULL;
for (;;) {
ts = runq_choose(tdq->ksq_curr);
if (ts == NULL) {
/*
* We already swapped once and didn't get anywhere.
*/
if (swap)
break;
swap = tdq->ksq_curr;
tdq->ksq_curr = tdq->ksq_next;
tdq->ksq_next = swap;
continue;
}
/*
* If we encounter a slice of 0 the td_sched is in a
* TIMESHARE td_sched group and its nice was too far out
* of the range that receives slices.
*/
nice = ts->ts_thread->td_proc->p_nice + (0 - tdq->ksq_nicemin);
#if 0
if (ts->ts_slice == 0 || (nice > SCHED_SLICE_NTHRESH &&
ts->ts_thread->td_proc->p_nice != 0)) {
runq_remove(ts->ts_runq, ts);
sched_slice(ts);
ts->ts_runq = tdq->ksq_next;
runq_add(ts->ts_runq, ts, 0);
continue;
}
#endif
return (ts);
}
return (runq_choose(&tdq->ksq_idle));
}
static void
tdq_setup(struct tdq *tdq)
{
runq_init(&tdq->ksq_timeshare[0]);
runq_init(&tdq->ksq_timeshare[1]);
runq_init(&tdq->ksq_idle);
tdq->ksq_curr = &tdq->ksq_timeshare[0];
tdq->ksq_next = &tdq->ksq_timeshare[1];
tdq->ksq_load = 0;
tdq->ksq_load_timeshare = 0;
}
static void
sched_setup(void *dummy)
{
#ifdef SMP
int i;
#endif
/*
* To avoid divide-by-zero, we set realstathz a dummy value
* in case which sched_clock() called before sched_initticks().
*/
realstathz = hz;
slice_min = (hz/100); /* 10ms */
slice_max = (hz/7); /* ~140ms */
#ifdef SMP
balance_groups = 0;
/*
* Initialize the tdqs.
*/
for (i = 0; i < MAXCPU; i++) {
struct tdq *ksq;
ksq = &tdq_cpu[i];
ksq->ksq_assigned = NULL;
tdq_setup(&tdq_cpu[i]);
}
if (smp_topology == NULL) {
struct tdq_group *ksg;
struct tdq *ksq;
int cpus;
for (cpus = 0, i = 0; i < MAXCPU; i++) {
if (CPU_ABSENT(i))
continue;
ksq = &tdq_cpu[i];
ksg = &tdq_groups[cpus];
/*
* Setup a tdq group with one member.
*/
ksq->ksq_transferable = 0;
ksq->ksq_group = ksg;
ksg->ksg_cpus = 1;
ksg->ksg_idlemask = 0;
ksg->ksg_cpumask = ksg->ksg_mask = 1 << i;
ksg->ksg_load = 0;
ksg->ksg_transferable = 0;
LIST_INIT(&ksg->ksg_members);
LIST_INSERT_HEAD(&ksg->ksg_members, ksq, ksq_siblings);
cpus++;
}
ksg_maxid = cpus - 1;
} else {
struct tdq_group *ksg;
struct cpu_group *cg;
int j;
for (i = 0; i < smp_topology->ct_count; i++) {
cg = &smp_topology->ct_group[i];
ksg = &tdq_groups[i];
/*
* Initialize the group.
*/
ksg->ksg_idlemask = 0;
ksg->ksg_load = 0;
ksg->ksg_transferable = 0;
ksg->ksg_cpus = cg->cg_count;
ksg->ksg_cpumask = cg->cg_mask;
LIST_INIT(&ksg->ksg_members);
/*
* Find all of the group members and add them.
*/
for (j = 0; j < MAXCPU; j++) {
if ((cg->cg_mask & (1 << j)) != 0) {
if (ksg->ksg_mask == 0)
ksg->ksg_mask = 1 << j;
tdq_cpu[j].ksq_transferable = 0;
tdq_cpu[j].ksq_group = ksg;
LIST_INSERT_HEAD(&ksg->ksg_members,
&tdq_cpu[j], ksq_siblings);
}
}
if (ksg->ksg_cpus > 1)
balance_groups = 1;
}
ksg_maxid = smp_topology->ct_count - 1;
}
/*
* Stagger the group and global load balancer so they do not
* interfere with each other.
*/
bal_tick = ticks + hz;
if (balance_groups)
gbal_tick = ticks + (hz / 2);
#else
tdq_setup(TDQ_SELF());
#endif
mtx_lock_spin(&sched_lock);
tdq_load_add(TDQ_SELF(), &td_sched0);
mtx_unlock_spin(&sched_lock);
}
/* ARGSUSED */
static void
sched_initticks(void *dummy)
{
mtx_lock_spin(&sched_lock);
realstathz = stathz ? stathz : hz;
slice_min = (realstathz/100); /* 10ms */
slice_max = (realstathz/7); /* ~140ms */
tickincr = (hz << 10) / realstathz;
/*
* XXX This does not work for values of stathz that are much
* larger than hz.
*/
if (tickincr == 0)
tickincr = 1;
mtx_unlock_spin(&sched_lock);
}
/*
* Scale the scheduling priority according to the "interactivity" of this
* process.
*/
static void
sched_priority(struct thread *td)
{
int pri;
if (td->td_pri_class != PRI_TIMESHARE)
return;
pri = SCHED_PRI_INTERACT(sched_interact_score(td));
pri += SCHED_PRI_BASE;
pri += td->td_proc->p_nice;
if (pri > PRI_MAX_TIMESHARE)
pri = PRI_MAX_TIMESHARE;
else if (pri < PRI_MIN_TIMESHARE)
pri = PRI_MIN_TIMESHARE;
sched_user_prio(td, pri);
return;
}
/*
* Calculate a time slice based on the properties of the process
* and the runq that we're on. This is only for PRI_TIMESHARE threads.
*/
static void
sched_slice(struct td_sched *ts)
{
struct tdq *tdq;
struct thread *td;
td = ts->ts_thread;
tdq = TDQ_CPU(ts->ts_cpu);
if (td->td_flags & TDF_BORROWING) {
ts->ts_slice = SCHED_SLICE_MIN;
return;
}
/*
* Rationale:
* Threads in interactive procs get a minimal slice so that we
* quickly notice if it abuses its advantage.
*
* Threads in non-interactive procs are assigned a slice that is
* based on the procs nice value relative to the least nice procs
* on the run queue for this cpu.
*
* If the thread is less nice than all others it gets the maximum
* slice and other threads will adjust their slice relative to
* this when they first expire.
*
* There is 20 point window that starts relative to the least
* nice td_sched on the run queue. Slice size is determined by
* the td_sched distance from the last nice thread.
*
* If the td_sched is outside of the window it will get no slice
* and will be reevaluated each time it is selected on the
* run queue. The exception to this is nice 0 procs when
* a nice -20 is running. They are always granted a minimum
* slice.
*/
if (!SCHED_INTERACTIVE(td)) {
int nice;
nice = td->td_proc->p_nice + (0 - tdq->ksq_nicemin);
if (tdq->ksq_load_timeshare == 0 ||
td->td_proc->p_nice < tdq->ksq_nicemin)
ts->ts_slice = SCHED_SLICE_MAX;
else if (nice <= SCHED_SLICE_NTHRESH)
ts->ts_slice = SCHED_SLICE_NICE(nice);
else if (td->td_proc->p_nice == 0)
ts->ts_slice = SCHED_SLICE_MIN;
else
ts->ts_slice = SCHED_SLICE_MIN; /* 0 */
} else
ts->ts_slice = SCHED_SLICE_INTERACTIVE;
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 routine will not operate correctly when slp or run times have been
* adjusted to more than double their maximum.
*/
static void
sched_interact_update(struct thread *td)
{
int sum;
sum = td->td_sched->skg_runtime + td->td_sched->skg_slptime;
if (sum < SCHED_SLP_RUN_MAX)
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) {
td->td_sched->skg_runtime /= 2;
td->td_sched->skg_slptime /= 2;
return;
}
td->td_sched->skg_runtime = (td->td_sched->skg_runtime / 5) * 4;
td->td_sched->skg_slptime = (td->td_sched->skg_slptime / 5) * 4;
}
static void
sched_interact_fork(struct thread *td)
{
int ratio;
int sum;
sum = td->td_sched->skg_runtime + td->td_sched->skg_slptime;
if (sum > SCHED_SLP_RUN_FORK) {
ratio = sum / SCHED_SLP_RUN_FORK;
td->td_sched->skg_runtime /= ratio;
td->td_sched->skg_slptime /= ratio;
}
}
static int
sched_interact_score(struct thread *td)
{
int div;
if (td->td_sched->skg_runtime > td->td_sched->skg_slptime) {
div = max(1, td->td_sched->skg_runtime / SCHED_INTERACT_HALF);
return (SCHED_INTERACT_HALF +
(SCHED_INTERACT_HALF - (td->td_sched->skg_slptime / div)));
} if (td->td_sched->skg_slptime > td->td_sched->skg_runtime) {
div = max(1, td->td_sched->skg_slptime / SCHED_INTERACT_HALF);
return (td->td_sched->skg_runtime / div);
}
/*
* This can happen if slptime and runtime are 0.
*/
return (0);
}
/*
* Very early in the boot some setup of scheduler-specific
* parts of proc0 and of soem scheduler resources needs to be done.
* Called from:
* proc0_init()
*/
void
schedinit(void)
{
/*
* Set up the scheduler specific parts of proc0.
*/
proc0.p_sched = NULL; /* XXX */
thread0.td_sched = &td_sched0;
td_sched0.ts_thread = &thread0;
td_sched0.ts_state = TSS_THREAD;
}
/*
* 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_MAX.
*/
int
sched_rr_interval(void)
{
return (SCHED_SLICE_MAX);
}
static void
sched_pctcpu_update(struct td_sched *ts)
{
/*
* Adjust counters and watermark for pctcpu calc.
*/
if (ts->ts_ltick > ticks - SCHED_CPU_TICKS) {
/*
* Shift the tick count out so that the divide doesn't
* round away our results.
*/
ts->ts_ticks <<= 10;
ts->ts_ticks = (ts->ts_ticks / (ticks - ts->ts_ftick)) *
SCHED_CPU_TICKS;
ts->ts_ticks >>= 10;
} else
ts->ts_ticks = 0;
ts->ts_ltick = ticks;
ts->ts_ftick = ts->ts_ltick - SCHED_CPU_TICKS;
}
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;
mtx_assert(&sched_lock, MA_OWNED);
if (td->td_priority == prio)
return;
if (TD_ON_RUNQ(td)) {
/*
* If the priority has been elevated due to priority
* propagation, we may have to move ourselves to a new
* queue. We still call adjustrunqueue below in case kse
* needs to fix things up.
*/
if (prio < td->td_priority && ts->ts_runq != NULL &&
(ts->ts_flags & TSF_ASSIGNED) == 0 &&
ts->ts_runq != TDQ_CPU(ts->ts_cpu)->ksq_curr) {
runq_remove(ts->ts_runq, ts);
ts->ts_runq = TDQ_CPU(ts->ts_cpu)->ksq_curr;
runq_add(ts->ts_runq, ts, 0);
}
/*
* Hold this td_sched on this cpu so that sched_prio() doesn't
* cause excessive migration. We only want migration to
* happen as the result of a wakeup.
*/
ts->ts_flags |= TSF_HOLD;
adjustrunqueue(td, prio);
ts->ts_flags &= ~TSF_HOLD;
} else
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);
}
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);
}
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);
}
void
sched_switch(struct thread *td, struct thread *newtd, int flags)
{
struct tdq *ksq;
struct td_sched *ts;
mtx_assert(&sched_lock, MA_OWNED);
ts = td->td_sched;
ksq = TDQ_SELF();
td->td_lastcpu = td->td_oncpu;
td->td_oncpu = NOCPU;
td->td_flags &= ~TDF_NEEDRESCHED;
td->td_owepreempt = 0;
/*
* If the thread has been assigned it may be in the process of switching
* to the new cpu. This is the case in sched_bind().
*/
if (td == PCPU_GET(idlethread)) {
TD_SET_CAN_RUN(td);
} else if ((ts->ts_flags & TSF_ASSIGNED) == 0) {
/* We are ending our run so make our slot available again */
tdq_load_rem(ksq, ts);
if (TD_IS_RUNNING(td)) {
/*
* Don't allow the thread to migrate
* from a preemption.
*/
ts->ts_flags |= TSF_HOLD;
setrunqueue(td, (flags & SW_PREEMPT) ?
SRQ_OURSELF|SRQ_YIELDING|SRQ_PREEMPTED :
SRQ_OURSELF|SRQ_YIELDING);
ts->ts_flags &= ~TSF_HOLD;
}
}
if (newtd != NULL) {
/*
* If we bring in a thread account for it as if it had been
* added to the run queue and then chosen.
*/
newtd->td_sched->ts_flags |= TSF_DIDRUN;
newtd->td_sched->ts_runq = ksq->ksq_curr;
TD_SET_RUNNING(newtd);
tdq_load_add(TDQ_SELF(), newtd->td_sched);
} else
newtd = choosethread();
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);
#ifdef HWPMC_HOOKS
if (PMC_PROC_IS_USING_PMCS(td->td_proc))
PMC_SWITCH_CONTEXT(td, PMC_FN_CSW_IN);
#endif
}
sched_lock.mtx_lock = (uintptr_t)td;
td->td_oncpu = PCPU_GET(cpuid);
}
void
sched_nice(struct proc *p, int nice)
{
struct td_sched *ts;
struct thread *td;
struct tdq *tdq;
PROC_LOCK_ASSERT(p, MA_OWNED);
mtx_assert(&sched_lock, MA_OWNED);
/*
* We need to adjust the nice counts for running threads.
*/
FOREACH_THREAD_IN_PROC(p, td) {
if (td->td_pri_class == PRI_TIMESHARE) {
ts = td->td_sched;
if (ts->ts_runq == NULL)
continue;
tdq = TDQ_CPU(ts->ts_cpu);
tdq_nice_rem(tdq, p->p_nice);
tdq_nice_add(tdq, nice);
}
}
p->p_nice = nice;
FOREACH_THREAD_IN_PROC(p, td) {
sched_priority(td);
td->td_flags |= TDF_NEEDRESCHED;
}
}
void
sched_sleep(struct thread *td)
{
mtx_assert(&sched_lock, MA_OWNED);
td->td_sched->ts_slptime = ticks;
}
void
sched_wakeup(struct thread *td)
{
mtx_assert(&sched_lock, MA_OWNED);
/*
* Let the procs know how long we slept for. This is because process
* interactivity behavior is modeled in the procs.
*/
if (td->td_sched->ts_slptime) {
int hzticks;
hzticks = (ticks - td->td_sched->ts_slptime) << 10;
if (hzticks >= SCHED_SLP_RUN_MAX) {
td->td_sched->skg_slptime = SCHED_SLP_RUN_MAX;
td->td_sched->skg_runtime = 1;
} else {
td->td_sched->skg_slptime += hzticks;
sched_interact_update(td);
}
sched_priority(td);
sched_slice(td->td_sched);
td->td_sched->ts_slptime = 0;
}
setrunqueue(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)
{
mtx_assert(&sched_lock, MA_OWNED);
sched_fork_thread(td, child);
}
void
sched_fork_thread(struct thread *td, struct thread *child)
{
struct td_sched *ts;
struct td_sched *ts2;
child->td_sched->skg_slptime = td->td_sched->skg_slptime;
child->td_sched->skg_runtime = td->td_sched->skg_runtime;
child->td_user_pri = td->td_user_pri;
child->td_base_user_pri = td->td_base_user_pri;
sched_interact_fork(child);
td->td_sched->skg_runtime += tickincr;
sched_interact_update(td);
sched_newthread(child);
ts = td->td_sched;
ts2 = child->td_sched;
ts2->ts_slice = 1; /* Attempt to quickly learn interactivity. */
ts2->ts_cpu = ts->ts_cpu;
ts2->ts_runq = NULL;
/* Grab our parents cpu estimation information. */
ts2->ts_ticks = ts->ts_ticks;
ts2->ts_ltick = ts->ts_ltick;
ts2->ts_ftick = ts->ts_ftick;
}
void
sched_class(struct thread *td, int class)
{
struct tdq *tdq;
struct td_sched *ts;
int nclass;
int oclass;
mtx_assert(&sched_lock, MA_OWNED);
if (td->td_pri_class == class)
return;
nclass = PRI_BASE(class);
oclass = PRI_BASE(td->td_pri_class);
ts = td->td_sched;
if (!((ts->ts_state != TSS_ONRUNQ &&
ts->ts_state != TSS_THREAD) || ts->ts_runq == NULL)) {
tdq = TDQ_CPU(ts->ts_cpu);
#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 (ts->ts_state == TSS_ONRUNQ) {
if (THREAD_CAN_MIGRATE(ts)) {
tdq->ksq_transferable--;
tdq->ksq_group->ksg_transferable--;
}
if (THREAD_CAN_MIGRATE(ts)) {
tdq->ksq_transferable++;
tdq->ksq_group->ksg_transferable++;
}
}
#endif
if (oclass == PRI_TIMESHARE) {
tdq->ksq_load_timeshare--;
tdq_nice_rem(tdq, td->td_proc->p_nice);
}
if (nclass == PRI_TIMESHARE) {
tdq->ksq_load_timeshare++;
tdq_nice_add(tdq, td->td_proc->p_nice);
}
}
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)
{
CTR3(KTR_SCHED, "sched_exit: %p(%s) prio %d",
child, child->td_proc->p_comm, child->td_priority);
sched_exit_thread(FIRST_THREAD_IN_PROC(p), child);
}
void
sched_exit_thread(struct thread *td, struct thread *child)
{
CTR3(KTR_SCHED, "sched_exit_thread: %p(%s) prio %d",
child, childproc->p_comm, child->td_priority);
td->td_sched->skg_runtime += child->td_sched->skg_runtime;
sched_interact_update(td);
tdq_load_rem(TDQ_CPU(child->td_sched->ts_cpu), child->td_sched);
}
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) {
mtx_lock_spin(&sched_lock);
td->td_priority = td->td_user_pri;
td->td_base_pri = td->td_user_pri;
mtx_unlock_spin(&sched_lock);
}
}
void
sched_clock(struct thread *td)
{
struct tdq *tdq;
struct td_sched *ts;
mtx_assert(&sched_lock, MA_OWNED);
tdq = TDQ_SELF();
#ifdef SMP
if (ticks >= bal_tick)
sched_balance();
if (ticks >= gbal_tick && balance_groups)
sched_balance_groups();
/*
* We could have been assigned a non real-time thread without an
* IPI.
*/
if (tdq->ksq_assigned)
tdq_assign(tdq); /* Potentially sets NEEDRESCHED */
#endif
ts = td->td_sched;
/* Adjust ticks for pctcpu */
ts->ts_ticks++;
ts->ts_ltick = ticks;
/* Go up to one second beyond our max and then trim back down */
if (ts->ts_ftick + SCHED_CPU_TICKS + hz < ts->ts_ltick)
sched_pctcpu_update(ts);
if (td->td_flags & TDF_IDLETD)
return;
/*
* 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->skg_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.
*/
tdq_load_rem(tdq, ts);
sched_priority(td);
sched_slice(ts);
if (SCHED_CURR(td, ts))
ts->ts_runq = tdq->ksq_curr;
else
ts->ts_runq = tdq->ksq_next;
tdq_load_add(tdq, ts);
td->td_flags |= TDF_NEEDRESCHED;
}
int
sched_runnable(void)
{
struct tdq *tdq;
int load;
load = 1;
tdq = TDQ_SELF();
#ifdef SMP
if (tdq->ksq_assigned) {
mtx_lock_spin(&sched_lock);
tdq_assign(tdq);
mtx_unlock_spin(&sched_lock);
}
#endif
if ((curthread->td_flags & TDF_IDLETD) != 0) {
if (tdq->ksq_load > 0)
goto out;
} else
if (tdq->ksq_load - 1 > 0)
goto out;
load = 0;
out:
return (load);
}
struct td_sched *
sched_choose(void)
{
struct tdq *tdq;
struct td_sched *ts;
mtx_assert(&sched_lock, MA_OWNED);
tdq = TDQ_SELF();
#ifdef SMP
restart:
if (tdq->ksq_assigned)
tdq_assign(tdq);
#endif
ts = tdq_choose(tdq);
if (ts) {
#ifdef SMP
if (ts->ts_thread->td_pri_class == PRI_IDLE)
if (tdq_idled(tdq) == 0)
goto restart;
#endif
tdq_runq_rem(tdq, ts);
ts->ts_state = TSS_THREAD;
ts->ts_flags &= ~TSF_PREEMPTED;
return (ts);
}
#ifdef SMP
if (tdq_idled(tdq) == 0)
goto restart;
#endif
return (NULL);
}
void
sched_add(struct thread *td, int flags)
{
struct tdq *tdq;
struct td_sched *ts;
int preemptive;
int canmigrate;
int class;
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);
mtx_assert(&sched_lock, MA_OWNED);
ts = td->td_sched;
canmigrate = 1;
preemptive = !(flags & SRQ_YIELDING);
class = PRI_BASE(td->td_pri_class);
tdq = TDQ_SELF();
ts->ts_flags &= ~TSF_INTERNAL;
#ifdef SMP
if (ts->ts_flags & TSF_ASSIGNED) {
if (ts->ts_flags & TSF_REMOVED)
ts->ts_flags &= ~TSF_REMOVED;
return;
}
canmigrate = THREAD_CAN_MIGRATE(ts);
/*
* Don't migrate running threads here. Force the long term balancer
* to do it.
*/
if (ts->ts_flags & TSF_HOLD) {
ts->ts_flags &= ~TSF_HOLD;
canmigrate = 0;
}
#endif
KASSERT(ts->ts_state != TSS_ONRUNQ,
("sched_add: thread %p (%s) already in run queue", td,
td->td_proc->p_comm));
KASSERT(td->td_proc->p_sflag & PS_INMEM,
("sched_add: process swapped out"));
KASSERT(ts->ts_runq == NULL,
("sched_add: thread %p is still assigned to a run queue", td));
if (flags & SRQ_PREEMPTED)
ts->ts_flags |= TSF_PREEMPTED;
switch (class) {
case PRI_ITHD:
case PRI_REALTIME:
ts->ts_runq = tdq->ksq_curr;
ts->ts_slice = SCHED_SLICE_MAX;
if (canmigrate)
ts->ts_cpu = PCPU_GET(cpuid);
break;
case PRI_TIMESHARE:
if (SCHED_CURR(td, ts))
ts->ts_runq = tdq->ksq_curr;
else
ts->ts_runq = tdq->ksq_next;
break;
case PRI_IDLE:
/*
* This is for priority prop.
*/
if (ts->ts_thread->td_priority < PRI_MIN_IDLE)
ts->ts_runq = tdq->ksq_curr;
else
ts->ts_runq = &tdq->ksq_idle;
ts->ts_slice = SCHED_SLICE_MIN;
break;
default:
panic("Unknown pri class.");
break;
}
#ifdef SMP
/*
* If this thread is pinned or bound, notify the target cpu.
*/
if (!canmigrate && ts->ts_cpu != PCPU_GET(cpuid) ) {
ts->ts_runq = NULL;
tdq_notify(ts, ts->ts_cpu);
return;
}
/*
* If we had been idle, clear our bit in the group and potentially
* the global bitmap. If not, see if we should transfer this thread.
*/
if ((class == PRI_TIMESHARE || class == PRI_REALTIME) &&
(tdq->ksq_group->ksg_idlemask & PCPU_GET(cpumask)) != 0) {
/*
* Check to see if our group is unidling, and if so, remove it
* from the global idle mask.
*/
if (tdq->ksq_group->ksg_idlemask ==
tdq->ksq_group->ksg_cpumask)
atomic_clear_int(&tdq_idle, tdq->ksq_group->ksg_mask);
/*
* Now remove ourselves from the group specific idle mask.
*/
tdq->ksq_group->ksg_idlemask &= ~PCPU_GET(cpumask);
} else if (canmigrate && tdq->ksq_load > 1 && class != PRI_ITHD)
if (tdq_transfer(tdq, ts, class))
return;
ts->ts_cpu = PCPU_GET(cpuid);
#endif
if (td->td_priority < curthread->td_priority &&
ts->ts_runq == tdq->ksq_curr)
curthread->td_flags |= TDF_NEEDRESCHED;
if (preemptive && maybe_preempt(td))
return;
ts->ts_state = TSS_ONRUNQ;
tdq_runq_add(tdq, ts, flags);
tdq_load_add(tdq, ts);
}
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);
mtx_assert(&sched_lock, MA_OWNED);
ts = td->td_sched;
ts->ts_flags &= ~TSF_PREEMPTED;
if (ts->ts_flags & TSF_ASSIGNED) {
ts->ts_flags |= TSF_REMOVED;
return;
}
KASSERT((ts->ts_state == TSS_ONRUNQ),
("sched_rem: thread not on run queue"));
ts->ts_state = TSS_THREAD;
tdq = TDQ_CPU(ts->ts_cpu);
tdq_runq_rem(tdq, ts);
tdq_load_rem(tdq, ts);
}
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);
mtx_lock_spin(&sched_lock);
if (ts->ts_ticks) {
int rtick;
/*
* Don't update more frequently than twice a second. Allowing
* this causes the cpu usage to decay away too quickly due to
* rounding errors.
*/
if (ts->ts_ftick + SCHED_CPU_TICKS < ts->ts_ltick ||
ts->ts_ltick < (ticks - (hz / 2)))
sched_pctcpu_update(ts);
/* How many rtick per second ? */
rtick = min(ts->ts_ticks / SCHED_CPU_TIME, SCHED_CPU_TICKS);
pctcpu = (FSCALE * ((FSCALE * rtick)/realstathz)) >> FSHIFT;
}
td->td_proc->p_swtime = ts->ts_ltick - ts->ts_ftick;
mtx_unlock_spin(&sched_lock);
return (pctcpu);
}
void
sched_bind(struct thread *td, int cpu)
{
struct td_sched *ts;
mtx_assert(&sched_lock, MA_OWNED);
ts = td->td_sched;
ts->ts_flags |= TSF_BOUND;
#ifdef SMP
if (PCPU_GET(cpuid) == cpu)
return;
/* sched_rem without the runq_remove */
ts->ts_state = TSS_THREAD;
tdq_load_rem(TDQ_CPU(ts->ts_cpu), ts);
tdq_notify(ts, cpu);
/* When we return from mi_switch we'll be on the correct cpu. */
mi_switch(SW_VOL, NULL);
#endif
}
void
sched_unbind(struct thread *td)
{
mtx_assert(&sched_lock, MA_OWNED);
td->td_sched->ts_flags &= ~TSF_BOUND;
}
int
sched_is_bound(struct thread *td)
{
mtx_assert(&sched_lock, MA_OWNED);
return (td->td_sched->ts_flags & TSF_BOUND);
}
void
sched_relinquish(struct thread *td)
{
mtx_lock_spin(&sched_lock);
if (td->td_pri_class == PRI_TIMESHARE)
sched_prio(td, PRI_MAX_TIMESHARE);
mi_switch(SW_VOL, NULL);
mtx_unlock_spin(&sched_lock);
}
int
sched_load(void)
{
#ifdef SMP
int total;
int i;
total = 0;
for (i = 0; i <= ksg_maxid; i++)
total += TDQ_GROUP(i)->ksg_load;
return (total);
#else
return (TDQ_SELF()->ksq_sysload);
#endif
}
int
sched_sizeof_proc(void)
{
return (sizeof(struct proc));
}
int
sched_sizeof_thread(void)
{
return (sizeof(struct thread) + sizeof(struct td_sched));
}
void
sched_tick(void)
{
}
#define KERN_SWITCH_INCLUDE 1
#include "kern/kern_switch.c"
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