d/freebsd-dev
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity
9f88fdfb88
freebsd-dev/sys/kern/sched_ule.c
Jeff Roberson a8949de20e - Keep seperate statistics and run queues for different scheduling classes. 
- Treat each class specially in kseq_{choose,add,rem}.  Let the rest of the
   code be less aware of scheduling classes.
 - Skip the interactivity calculation for non TIMESHARE ksegrps.
 - Move slice and runq selection into kseq_add().  Uninline it now that it's
   big.
2003-04-03 00:29:28 +00:00

1064 lines
24 KiB
C
Raw Blame History

/*-
* Copyright (c) 2003, 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.
*
* $FreeBSD$
*/
#include <sys/param.h>
#include <sys/systm.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/sched.h>
#include <sys/smp.h>
#include <sys/sx.h>
#include <sys/sysctl.h>
#include <sys/sysproto.h>
#include <sys/vmmeter.h>
#ifdef DDB
#include <ddb/ddb.h>
#endif
#ifdef KTRACE
#include <sys/uio.h>
#include <sys/ktrace.h>
#endif
#include <machine/cpu.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)
int realstathz;
#define SCHED_STRICT_RESCHED 1
/*
* These datastructures are allocated within their parent datastructure but
* are scheduler specific.
*/
struct ke_sched {
int ske_slice;
struct runq *ske_runq;
/* The following variables are only used for pctcpu calculation */
int ske_ltick; /* Last tick that we were running on */
int ske_ftick; /* First tick that we were running on */
int ske_ticks; /* Tick count */
u_char ske_cpu;
};
#define ke_slice ke_sched->ske_slice
#define ke_runq ke_sched->ske_runq
#define ke_ltick ke_sched->ske_ltick
#define ke_ftick ke_sched->ske_ftick
#define ke_ticks ke_sched->ske_ticks
#define ke_cpu ke_sched->ske_cpu
struct kg_sched {
int skg_slptime; /* Number of ticks we vol. slept */
int skg_runtime; /* Number of ticks we were running */
};
#define kg_slptime kg_sched->skg_slptime
#define kg_runtime kg_sched->skg_runtime
struct td_sched {
int std_slptime;
int std_schedflag;
};
#define td_slptime td_sched->std_slptime
#define td_schedflag td_sched->std_schedflag
#define TD_SCHED_BLOAD 0x0001 /*
* thread was counted as being in short
* term sleep.
*/
struct td_sched td_sched;
struct ke_sched ke_sched;
struct kg_sched kg_sched;
struct ke_sched *kse0_sched = &ke_sched;
struct kg_sched *ksegrp0_sched = &kg_sched;
struct p_sched *proc0_sched = NULL;
struct td_sched *thread0_sched = &td_sched;
/*
* This priority range has 20 priorities on either end that are reachable
* only through nice values.
*
* PRI_RANGE: Total priority range for timeshare threads.
* PRI_NRESV: Reserved priorities for nice.
* PRI_BASE: The start of the dynamic range.
* DYN_RANGE: Number of priorities that are available int the dynamic
* priority range.
* DYN_HALF: Half of DYN_RANGE for convenience elsewhere.
* PRI_DYN: The dynamic priority which is derived from the number of ticks
* running vs the total number of ticks.
*/
#define SCHED_PRI_RANGE (PRI_MAX_TIMESHARE - PRI_MIN_TIMESHARE + 1)
#define SCHED_PRI_NRESV PRIO_TOTAL
#define SCHED_PRI_NHALF (PRIO_TOTAL / 2)
#define SCHED_PRI_BASE ((SCHED_PRI_NRESV / 2) + PRI_MIN_TIMESHARE)
#define SCHED_DYN_RANGE (SCHED_PRI_RANGE - SCHED_PRI_NRESV)
#define SCHED_DYN_HALF (SCHED_DYN_RANGE / 2)
#define SCHED_PRI_DYN(run, total) (((run) * SCHED_DYN_RANGE) / (total))
/*
* 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_THROTTLE: Divisor for reducing slp/run time.
* INTERACT_RANGE: Range of interactivity values. Smaller is better.
* INTERACT_HALF: Convenience define, half of the interactivity range.
* INTERACT_THRESH: Threshhold for placement on the current runq.
*/
#define SCHED_SLP_RUN_MAX ((hz * 2) << 10)
#define SCHED_SLP_RUN_THROTTLE (10)
#define SCHED_INTERACT_RANGE (100)
#define SCHED_INTERACT_HALF (SCHED_INTERACT_RANGE / 2)
#define SCHED_INTERACT_THRESH (10)
/*
* 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.
*/
#define SCHED_SLICE_MIN (hz / 100)
#define SCHED_SLICE_MAX (hz / 10)
#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_PRI_NHALF))
/*
* This macro determines whether or not the kse belongs on the current or
* next run queue.
*
* XXX nice value should effect how interactive a kg is.
*/
#define SCHED_CURR(kg) (sched_interact_score(kg) < SCHED_INTERACT_THRESH)
/*
* 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)
/*
* kseq - pair of runqs per processor
*/
struct kseq {
struct runq ksq_ithd; /* Queue of ITHD and REALTIME tds. */
struct runq ksq_idle; /* Queue of IDLE threads. */
struct runq ksq_runqs[2]; /* Run queues for TIMESHARE. */
struct runq *ksq_curr;
struct runq *ksq_next;
int ksq_itload; /* Total runnable for ITHD. */
int ksq_tsload; /* Total runnable for TIMESHARE. */
int ksq_idload; /* Total runnable for IDLE. */
#ifdef SMP
unsigned int ksq_rslices; /* Slices on run queue */
unsigned int ksq_bload; /* Threads waiting on IO */
#endif
};
/*
* One kse queue per processor.
*/
#ifdef SMP
struct kseq kseq_cpu[MAXCPU];
#define KSEQ_SELF() (&kseq_cpu[PCPU_GET(cpuid)])
#define KSEQ_CPU(x) (&kseq_cpu[(x)])
#else
struct kseq kseq_cpu;
#define KSEQ_SELF() (&kseq_cpu)
#define KSEQ_CPU(x) (&kseq_cpu)
#endif
static void sched_slice(struct kse *ke);
static int sched_priority(struct ksegrp *kg);
static int sched_interact_score(struct ksegrp *kg);
void sched_pctcpu_update(struct kse *ke);
int sched_pickcpu(void);
/* Operations on per processor queues */
static struct kse * kseq_choose(struct kseq *kseq);
static int kseq_nice_min(struct kseq *kseq);
static void kseq_setup(struct kseq *kseq);
static void kseq_add(struct kseq *kseq, struct kse *ke);
static __inline void kseq_rem(struct kseq *kseq, struct kse *ke);
#ifdef SMP
static __inline void kseq_sleep(struct kseq *kseq, struct kse *ke);
static __inline void kseq_wakeup(struct kseq *kseq, struct kse *ke);
struct kseq * kseq_load_highest(void);
#endif
static void
kseq_add(struct kseq *kseq, struct kse *ke)
{
struct ksegrp *kg;
kg = ke->ke_ksegrp;
/*
* Figure out what run queue we should go on and assign a slice.
*/
switch (kg->kg_pri_class) {
/*
* If we're a real-time or interrupt thread place us on the curr
* queue for the current processor. Hopefully this will yield the
* lowest latency response.
*/
case PRI_ITHD:
case PRI_REALTIME:
ke->ke_runq = &kseq->ksq_ithd;
ke->ke_slice = SCHED_SLICE_MAX;
kseq->ksq_itload++;
break;
/*
* Timeshare threads get placed on the appropriate queue on their
* bound cpu.
*/
case PRI_TIMESHARE:
if (ke->ke_runq == NULL) {
if (SCHED_CURR(kg))
ke->ke_runq = kseq->ksq_curr;
else
ke->ke_runq = kseq->ksq_next;
}
if (ke->ke_slice == 0)
sched_slice(ke);
kseq->ksq_tsload++;
break;
/*
* Only grant PRI_IDLE processes a slice if there is nothing else
* running.
*/
case PRI_IDLE:
ke->ke_runq = &kseq->ksq_idle;
ke->ke_slice = SCHED_SLICE_MIN;
kseq->ksq_idload++;
break;
default:
panic("Unknown priority class.\n");
break;
}
runq_add(ke->ke_runq, ke);
#ifdef SMP
kseq->ksq_rslices += ke->ke_slice;
#endif
}
static void
kseq_rem(struct kseq *kseq, struct kse *ke)
{
struct ksegrp *kg;
kg = ke->ke_ksegrp;
/*
* XXX Consider making the load an array.
*/
switch (kg->kg_pri_class) {
case PRI_ITHD:
case PRI_REALTIME:
kseq->ksq_itload--;
break;
case PRI_TIMESHARE:
kseq->ksq_tsload--;
break;
case PRI_IDLE:
kseq->ksq_idload--;
break;
}
runq_remove(ke->ke_runq, ke);
#ifdef SMP
kseq->ksq_rslices -= ke->ke_slice;
#endif
}
#ifdef SMP
static __inline void
kseq_sleep(struct kseq *kseq, struct kse *ke)
{
kseq->ksq_bload++;
}
static __inline void
kseq_wakeup(struct kseq *kseq, struct kse *ke)
{
kseq->ksq_bload--;
}
struct kseq *
kseq_load_highest(void)
{
struct kseq *kseq;
int load;
int cpu;
int i;
cpu = 0;
load = 0;
for (i = 0; i < mp_maxid; i++) {
if (CPU_ABSENT(i))
continue;
kseq = KSEQ_CPU(i);
if (kseq->ksq_tsload > load) {
load = kseq->ksq_tsload;
cpu = i;
}
}
if (load)
return (KSEQ_CPU(cpu));
return (NULL);
}
#endif
struct kse *
kseq_choose(struct kseq *kseq)
{
struct kse *ke;
struct runq *swap;
if (kseq->ksq_itload)
return (runq_choose(&kseq->ksq_ithd));
if (kseq->ksq_tsload) {
if ((ke = runq_choose(kseq->ksq_curr)) != NULL)
return (ke);
swap = kseq->ksq_curr;
kseq->ksq_curr = kseq->ksq_next;
kseq->ksq_next = swap;
return (runq_choose(kseq->ksq_curr));
}
if (kseq->ksq_idload)
return (runq_choose(&kseq->ksq_idle));
return (NULL);
}
static int
kseq_nice_min(struct kseq *kseq)
{
struct kse *ke0;
struct kse *ke1;
if (kseq->ksq_tsload == 0)
return (0);
ke0 = runq_choose(kseq->ksq_curr);
ke1 = runq_choose(kseq->ksq_next);
if (ke0 == NULL)
return (ke1->ke_ksegrp->kg_nice);
if (ke1 == NULL)
return (ke0->ke_ksegrp->kg_nice);
return (min(ke0->ke_ksegrp->kg_nice, ke1->ke_ksegrp->kg_nice));
}
static void
kseq_setup(struct kseq *kseq)
{
kseq->ksq_curr = &kseq->ksq_runqs[0];
kseq->ksq_next = &kseq->ksq_runqs[1];
runq_init(&kseq->ksq_ithd);
runq_init(kseq->ksq_curr);
runq_init(kseq->ksq_next);
runq_init(&kseq->ksq_idle);
kseq->ksq_itload = 0;
kseq->ksq_tsload = 0;
kseq->ksq_idload = 0;
#ifdef SMP
kseq->ksq_rslices = 0;
kseq->ksq_bload = 0;
#endif
}
static void
sched_setup(void *dummy)
{
int i;
realstathz = stathz ? stathz : hz;
mtx_lock_spin(&sched_lock);
/* init kseqs */
for (i = 0; i < MAXCPU; i++)
kseq_setup(KSEQ_CPU(i));
mtx_unlock_spin(&sched_lock);
}
/*
* Scale the scheduling priority according to the "interactivity" of this
* process.
*/
static int
sched_priority(struct ksegrp *kg)
{
int pri;
if (kg->kg_pri_class != PRI_TIMESHARE)
return (kg->kg_user_pri);
pri = sched_interact_score(kg) * SCHED_DYN_RANGE / SCHED_INTERACT_RANGE;
pri += SCHED_PRI_BASE;
pri += kg->kg_nice;
if (pri > PRI_MAX_TIMESHARE)
pri = PRI_MAX_TIMESHARE;
else if (pri < PRI_MIN_TIMESHARE)
pri = PRI_MIN_TIMESHARE;
kg->kg_user_pri = pri;
return (kg->kg_user_pri);
}
/*
* Calculate a time slice based on the properties of the kseg and the runq
* that we're on. This is only for PRI_TIMESHARE ksegrps.
*/
static void
sched_slice(struct kse *ke)
{
struct ksegrp *kg;
kg = ke->ke_ksegrp;
/*
* Rationale:
* KSEs in interactive ksegs get the minimum slice so that we
* quickly notice if it abuses its advantage.
*
* KSEs in non-interactive ksegs are assigned a slice that is
* based on the ksegs nice value relative to the least nice kseg
* on the run queue for this cpu.
*
* If the KSE is less nice than all others it gets the maximum
* slice and other KSEs will adjust their slice relative to
* this when they first expire.
*
* There is 20 point window that starts relative to the least
* nice kse on the run queue. Slice size is determined by
* the kse distance from the last nice ksegrp.
*
* If you are outside of the window you will get no slice and
* you will be reevaluated each time you are selected on the
* run queue.
*
*/
if (!SCHED_CURR(kg)) {
struct kseq *kseq;
int nice_base;
int nice;
kseq = KSEQ_CPU(ke->ke_cpu);
nice_base = kseq_nice_min(kseq);
nice = kg->kg_nice + (0 - nice_base);
if (kseq->ksq_tsload == 0 || kg->kg_nice < nice_base)
ke->ke_slice = SCHED_SLICE_MAX;
else if (nice <= SCHED_PRI_NHALF)
ke->ke_slice = SCHED_SLICE_NICE(nice);
else
ke->ke_slice = 0;
} else
ke->ke_slice = SCHED_SLICE_MIN;
/*
* Check to see if we need to scale back the slp and run time
* in the kg. This will cause us to forget old interactivity
* while maintaining the current ratio.
*/
if ((kg->kg_runtime + kg->kg_slptime) > SCHED_SLP_RUN_MAX) {
kg->kg_runtime /= SCHED_SLP_RUN_THROTTLE;
kg->kg_slptime /= SCHED_SLP_RUN_THROTTLE;
}
return;
}
static int
sched_interact_score(struct ksegrp *kg)
{
int big;
int small;
int base;
if (kg->kg_runtime > kg->kg_slptime) {
big = kg->kg_runtime;
small = kg->kg_slptime;
base = SCHED_INTERACT_HALF;
} else {
big = kg->kg_slptime;
small = kg->kg_runtime;
base = 0;
}
big /= SCHED_INTERACT_HALF;
if (big != 0)
small /= big;
else
small = 0;
small += base;
/* XXX Factor in nice */
return (small);
}
int
sched_rr_interval(void)
{
return (SCHED_SLICE_MAX);
}
void
sched_pctcpu_update(struct kse *ke)
{
/*
* Adjust counters and watermark for pctcpu calc.
*/
/*
* Shift the tick count out so that the divide doesn't round away
* our results.
*/
ke->ke_ticks <<= 10;
ke->ke_ticks = (ke->ke_ticks / (ke->ke_ltick - ke->ke_ftick)) *
SCHED_CPU_TICKS;
ke->ke_ticks >>= 10;
ke->ke_ltick = ticks;
ke->ke_ftick = ke->ke_ltick - SCHED_CPU_TICKS;
}
#ifdef SMP
/* XXX Should be changed to kseq_load_lowest() */
int
sched_pickcpu(void)
{
struct kseq *kseq;
int load;
int cpu;
int i;
if (!smp_started)
return (0);
load = 0;
cpu = 0;
for (i = 0; i < mp_maxid; i++) {
if (CPU_ABSENT(i))
continue;
kseq = KSEQ_CPU(i);
if (kseq->ksq_tsload < load) {
cpu = i;
load = kseq->ksq_tsload;
}
}
CTR1(KTR_RUNQ, "sched_pickcpu: %d", cpu);
return (cpu);
}
#else
int
sched_pickcpu(void)
{
return (0);
}
#endif
void
sched_prio(struct thread *td, u_char prio)
{
struct kse *ke;
struct runq *rq;
mtx_assert(&sched_lock, MA_OWNED);
ke = td->td_kse;
td->td_priority = prio;
if (TD_ON_RUNQ(td)) {
rq = ke->ke_runq;
runq_remove(rq, ke);
runq_add(rq, ke);
}
}
void
sched_switchout(struct thread *td)
{
struct kse *ke;
mtx_assert(&sched_lock, MA_OWNED);
ke = td->td_kse;
td->td_last_kse = ke;
td->td_lastcpu = ke->ke_oncpu;
ke->ke_oncpu = NOCPU;
td->td_flags &= ~TDF_NEEDRESCHED;
if (TD_IS_RUNNING(td)) {
setrunqueue(td);
return;
}
td->td_kse->ke_runq = NULL;
/*
* We will not be on the run queue. So we must be
* sleeping or similar.
*/
if (td->td_proc->p_flag & P_THREADED)
kse_reassign(ke);
}
void
sched_switchin(struct thread *td)
{
/* struct kse *ke = td->td_kse; */
mtx_assert(&sched_lock, MA_OWNED);
td->td_kse->ke_oncpu = PCPU_GET(cpuid);
#if SCHED_STRICT_RESCHED
if (td->td_ksegrp->kg_pri_class == PRI_TIMESHARE &&
td->td_priority != td->td_ksegrp->kg_user_pri)
curthread->td_flags |= TDF_NEEDRESCHED;
#endif
}
void
sched_nice(struct ksegrp *kg, int nice)
{
struct thread *td;
kg->kg_nice = nice;
sched_priority(kg);
FOREACH_THREAD_IN_GROUP(kg, td) {
td->td_flags |= TDF_NEEDRESCHED;
}
}
void
sched_sleep(struct thread *td, u_char prio)
{
mtx_assert(&sched_lock, MA_OWNED);
td->td_slptime = ticks;
td->td_priority = prio;
#ifdef SMP
if (td->td_priority < PZERO) {
kseq_sleep(KSEQ_CPU(td->td_kse->ke_cpu), td->td_kse);
td->td_schedflag |= TD_SCHED_BLOAD;
}
#endif
}
void
sched_wakeup(struct thread *td)
{
mtx_assert(&sched_lock, MA_OWNED);
/*
* Let the kseg know how long we slept for. This is because process
* interactivity behavior is modeled in the kseg.
*/
if (td->td_slptime) {
struct ksegrp *kg;
kg = td->td_ksegrp;
kg->kg_slptime += (ticks - td->td_slptime) << 10;
sched_priority(kg);
td->td_slptime = 0;
}
#ifdef SMP
if (td->td_priority < PZERO && td->td_schedflag & TD_SCHED_BLOAD) {
kseq_wakeup(KSEQ_CPU(td->td_kse->ke_cpu), td->td_kse);
td->td_schedflag &= ~TD_SCHED_BLOAD;
}
#endif
setrunqueue(td);
#if SCHED_STRICT_RESCHED
if (td->td_priority < curthread->td_priority)
curthread->td_flags |= TDF_NEEDRESCHED;
#endif
}
/*
* Penalize the parent for creating a new child and initialize the child's
* priority.
*/
void
sched_fork(struct ksegrp *kg, struct ksegrp *child)
{
struct kse *ckse;
struct kse *pkse;
mtx_assert(&sched_lock, MA_OWNED);
ckse = FIRST_KSE_IN_KSEGRP(child);
pkse = FIRST_KSE_IN_KSEGRP(kg);
/* XXX Need something better here */
if (kg->kg_slptime > kg->kg_runtime) {
child->kg_slptime = SCHED_DYN_RANGE;
child->kg_runtime = kg->kg_slptime / SCHED_DYN_RANGE;
} else {
child->kg_runtime = SCHED_DYN_RANGE;
child->kg_slptime = kg->kg_runtime / SCHED_DYN_RANGE;
}
#if 0
child->kg_slptime = kg->kg_slptime;
child->kg_runtime = kg->kg_runtime;
#endif
child->kg_user_pri = kg->kg_user_pri;
#if 0
if (pkse->ke_cpu != PCPU_GET(cpuid)) {
printf("pkse->ke_cpu = %d\n", pkse->ke_cpu);
printf("cpuid = %d", PCPU_GET(cpuid));
Debugger("stop");
}
#endif
ckse->ke_slice = pkse->ke_slice;
ckse->ke_cpu = pkse->ke_cpu; /* sched_pickcpu(); */
ckse->ke_runq = NULL;
/*
* Claim that we've been running for one second for statistical
* purposes.
*/
ckse->ke_ticks = 0;
ckse->ke_ltick = ticks;
ckse->ke_ftick = ticks - hz;
}
/*
* Return some of the child's priority and interactivity to the parent.
*/
void
sched_exit(struct ksegrp *kg, struct ksegrp *child)
{
/* XXX Need something better here */
mtx_assert(&sched_lock, MA_OWNED);
#if 0
kg->kg_slptime = child->kg_slptime;
kg->kg_runtime = child->kg_runtime;
sched_priority(kg);
#endif
}
void
sched_clock(struct thread *td)
{
struct kse *ke;
#if SCHED_STRICT_RESCHED
struct kse *nke;
struct kseq *kseq;
#endif
struct ksegrp *kg;
ke = td->td_kse;
kg = td->td_ksegrp;
mtx_assert(&sched_lock, MA_OWNED);
KASSERT((td != NULL), ("schedclock: null thread pointer"));
/* Adjust ticks for pctcpu */
ke->ke_ticks++;
ke->ke_ltick = ticks;
/* Go up to one second beyond our max and then trim back down */
if (ke->ke_ftick + SCHED_CPU_TICKS + hz < ke->ke_ltick)
sched_pctcpu_update(ke);
if (td->td_kse->ke_flags & KEF_IDLEKSE)
return;
/*
* Check for a higher priority task on the run queue. This can happen
* on SMP if another processor woke up a process on our runq.
*/
#if SCHED_STRICT_RESCHED
kseq = KSEQ_SELF();
nke = runq_choose(kseq->ksq_curr);
if (nke && nke->ke_thread &&
nke->ke_thread->td_priority < td->td_priority)
td->td_flags |= TDF_NEEDRESCHED;
#endif
/*
* We only do slicing code for TIMESHARE ksegrps.
*/
if (kg->kg_pri_class != PRI_TIMESHARE)
return;
/*
* We used a tick charge it to the ksegrp so that we can compute our
* "interactivity".
*/
kg->kg_runtime += 1 << 10;
/*
* We used up one time slice.
*/
ke->ke_slice--;
/*
* We're out of time, recompute priorities and requeue. We'll get a
* new slice when we're put back on the run queue.
*/
if (ke->ke_slice <= 0) {
sched_priority(kg);
td->td_flags |= TDF_NEEDRESCHED;
ke->ke_runq = NULL;
}
}
int
sched_runnable(void)
{
struct kseq *kseq;
kseq = KSEQ_SELF();
if (kseq->ksq_tsload || kseq->ksq_idload || kseq->ksq_itload)
return (1);
#ifdef SMP
/*
* For SMP we may steal other processor's KSEs. Just search until we
* verify that at least on other cpu has a runnable task.
*/
if (smp_started) {
int i;
#if 0
if (kseq->ksq_bload)
return (0);
#endif
for (i = 0; i < mp_maxid; i++) {
if (CPU_ABSENT(i))
continue;
kseq = KSEQ_CPU(i);
if (kseq->ksq_tsload)
return (1);
}
}
#endif
return (0);
}
void
sched_userret(struct thread *td)
{
struct ksegrp *kg;
kg = td->td_ksegrp;
if (td->td_priority != kg->kg_user_pri) {
mtx_lock_spin(&sched_lock);
td->td_priority = kg->kg_user_pri;
mtx_unlock_spin(&sched_lock);
}
}
struct kse *
sched_choose(void)
{
struct kseq *kseq;
struct kse *ke;
kseq = KSEQ_SELF();
retry:
ke = kseq_choose(kseq);
if (ke) {
ke->ke_state = KES_THREAD;
kseq_rem(kseq, ke);
/*
* If we dequeue a kse with a slice of zero it was below the
* nice threshold to acquire a slice. Force it on to the
* next run queue and let kseq_add() pick a new slice.
*
* XXX This code should live in a TIMESHARE specific section.
*/
if (ke->ke_slice == 0) {
ke->ke_runq = kseq->ksq_next;
kseq_add(kseq, ke);
goto retry;
}
}
#ifdef SMP
if (ke == NULL && smp_started) {
#if 0
if (kseq->ksq_bload)
return (NULL);
#endif
/*
* Find the cpu with the highest load and steal one proc.
*/
kseq = kseq_load_highest();
if (kseq == NULL)
return (NULL);
/*
* XXX Do we want to migrate interrupt or realtime threads?
* Currently we'll only try to steal if there is a TIMESHARE
* thread available but we will steal a REALTIME or interrupt
*/
ke = kseq_choose(kseq);
kseq_rem(kseq, ke);
ke->ke_state = KES_THREAD;
ke->ke_runq = NULL;
ke->ke_cpu = PCPU_GET(cpuid);
}
#endif
return (ke);
}
void
sched_add(struct kse *ke)
{
struct kseq *kseq;
mtx_assert(&sched_lock, MA_OWNED);
KASSERT((ke->ke_thread != NULL), ("sched_add: No thread on KSE"));
KASSERT((ke->ke_thread->td_kse != NULL),
("sched_add: No KSE on thread"));
KASSERT(ke->ke_state != KES_ONRUNQ,
("sched_add: kse %p (%s) already in run queue", ke,
ke->ke_proc->p_comm));
KASSERT(ke->ke_proc->p_sflag & PS_INMEM,
("sched_add: process swapped out"));
switch (ke->ke_ksegrp->kg_pri_class) {
case PRI_ITHD:
case PRI_REALTIME:
kseq = KSEQ_SELF();
break;
case PRI_TIMESHARE:
case PRI_IDLE:
default:
kseq = KSEQ_CPU(ke->ke_cpu);
break;
}
ke->ke_ksegrp->kg_runq_kses++;
ke->ke_state = KES_ONRUNQ;
kseq_add(kseq, ke);
}
void
sched_rem(struct kse *ke)
{
mtx_assert(&sched_lock, MA_OWNED);
/* KASSERT((ke->ke_state == KES_ONRUNQ), ("KSE not on run queue")); */
ke->ke_runq = NULL;
ke->ke_state = KES_THREAD;
ke->ke_ksegrp->kg_runq_kses--;
kseq_rem(KSEQ_CPU(ke->ke_cpu), ke);
}
fixpt_t
sched_pctcpu(struct kse *ke)
{
fixpt_t pctcpu;
int realstathz;
pctcpu = 0;
realstathz = stathz ? stathz : hz;
if (ke->ke_ticks) {
int rtick;
/* Update to account for time potentially spent sleeping */
ke->ke_ltick = ticks;
sched_pctcpu_update(ke);
/* How many rtick per second ? */
rtick = ke->ke_ticks / SCHED_CPU_TIME;
pctcpu = (FSCALE * ((FSCALE * rtick)/realstathz)) >> FSHIFT;
}
ke->ke_proc->p_swtime = ke->ke_ltick - ke->ke_ftick;
return (pctcpu);
}
int
sched_sizeof_kse(void)
{
return (sizeof(struct kse) + sizeof(struct ke_sched));
}
int
sched_sizeof_ksegrp(void)
{
return (sizeof(struct ksegrp) + sizeof(struct kg_sched));
}
int
sched_sizeof_proc(void)
{
return (sizeof(struct proc));
}
int
sched_sizeof_thread(void)
{
return (sizeof(struct thread) + sizeof(struct td_sched));
}
Reference in New Issue View Git Blame Copy Permalink