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NetBSD/sys/kern/sched_m2.c

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/* $NetBSD: sched_m2.c,v 1.13 2007/12/05 07:06:54 ad Exp $ */
/*
* Copyright (c) 2007, Mindaugas Rasiukevicius <rmind at NetBSD 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, 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 COPYRIGHT HOLDERS AND CONTRIBUTORS
* ``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 FOUNDATION OR CONTRIBUTORS
* 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.
*/
/*
* TODO:
* - Implementation of fair share queue;
* - Support for NUMA;
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: sched_m2.c,v 1.13 2007/12/05 07:06:54 ad Exp $");
#include <sys/param.h>
#include <sys/bitops.h>
#include <sys/cpu.h>
#include <sys/callout.h>
#include <sys/errno.h>
#include <sys/kernel.h>
#include <sys/kmem.h>
#include <sys/lwp.h>
#include <sys/mutex.h>
#include <sys/pool.h>
#include <sys/proc.h>
#include <sys/resource.h>
#include <sys/resourcevar.h>
#include <sys/sched.h>
#include <sys/syscallargs.h>
#include <sys/sysctl.h>
#include <sys/types.h>
/*
* Priority related defintions.
*/
#define PRI_TS_COUNT (NPRI_USER)
#define PRI_RT_COUNT (PRI_COUNT - PRI_TS_COUNT)
#define PRI_HTS_RANGE (PRI_TS_COUNT / 10)
#define PRI_HIGHEST_TS (MAXPRI_USER)
#define PRI_DEFAULT (NPRI_USER >> 1)
const int schedppq = 1;
/*
* Bits per map.
*/
#define BITMAP_BITS (32)
#define BITMAP_SHIFT (5)
#define BITMAP_MSB (0x80000000U)
#define BITMAP_MASK (BITMAP_BITS - 1)
/*
* Time-slices and priorities.
*/
static u_int min_ts; /* Minimal time-slice */
static u_int max_ts; /* Maximal time-slice */
static u_int rt_ts; /* Real-time time-slice */
static u_int ts_map[PRI_COUNT]; /* Map of time-slices */
static pri_t high_pri[PRI_COUNT]; /* Map for priority increase */
/*
* Migration and balancing.
*/
#ifdef MULTIPROCESSOR
static u_int cacheht_time; /* Cache hotness time */
static u_int min_catch; /* Minimal LWP count for catching */
static u_int balance_period; /* Balance period */
static struct callout balance_ch; /* Callout of balancer */
static struct cpu_info * volatile worker_ci;
#define CACHE_HOT(sil) (sil->sl_lrtime && \
(hardclock_ticks - sil->sl_lrtime < cacheht_time))
#endif
/*
* Structures, runqueue.
*/
typedef struct {
TAILQ_HEAD(, lwp) q_head;
} queue_t;
typedef struct {
/* Lock and bitmap */
kmutex_t r_rq_mutex;
uint32_t r_bitmap[PRI_COUNT >> BITMAP_SHIFT];
/* Counters */
u_int r_count; /* Count of the threads */
pri_t r_highest_pri; /* Highest priority */
u_int r_avgcount; /* Average count of threads */
u_int r_mcount; /* Count of migratable threads */
/* Runqueues */
queue_t r_rt_queue[PRI_RT_COUNT];
queue_t r_ts_queue[PRI_TS_COUNT];
} runqueue_t;
typedef struct {
u_int sl_flags;
u_int sl_timeslice; /* Time-slice of thread */
u_int sl_slept; /* Saved sleep time for sleep sum */
u_int sl_slpsum; /* Sum of sleep time */
u_int sl_rtime; /* Saved start time of run */
u_int sl_rtsum; /* Sum of the run time */
u_int sl_lrtime; /* Last run time */
} sched_info_lwp_t;
/* Flags */
#define SL_BATCH 0x01
/* Pool of the scheduler-specific structures for threads */
static struct pool sil_pool;
/*
* Prototypes.
*/
static inline void * sched_getrq(runqueue_t *, const pri_t);
static inline void sched_newts(struct lwp *);
static void sched_precalcts(void);
#ifdef MULTIPROCESSOR
static struct lwp * sched_catchlwp(void);
static void sched_balance(void *);
#endif
/*
* Initialization and setup.
*/
void
sched_rqinit(void)
{
struct cpu_info *ci = curcpu();
if (hz < 100) {
panic("sched_rqinit: value of HZ is too low\n");
}
/* Default timing ranges */
min_ts = mstohz(50); /* ~50ms */
max_ts = mstohz(150); /* ~150ms */
rt_ts = mstohz(100); /* ~100ms */
sched_precalcts();
#ifdef MULTIPROCESSOR
/* Balancing */
worker_ci = ci;
cacheht_time = mstohz(5); /* ~5 ms */
balance_period = mstohz(300); /* ~300ms */
min_catch = ~0;
#endif
/* Pool of the scheduler-specific structures */
pool_init(&sil_pool, sizeof(sched_info_lwp_t), 0, 0, 0,
"lwpsd", &pool_allocator_nointr, IPL_NONE);
/* Attach the primary CPU here */
sched_cpuattach(ci);
/* Initialize the scheduler structure of the primary LWP */
lwp0.l_mutex = &ci->ci_schedstate.spc_lwplock;
sched_lwp_fork(NULL, &lwp0);
sched_newts(&lwp0);
}
void
sched_setup(void)
{
#ifdef MULTIPROCESSOR
/* Minimal count of LWPs for catching: log2(count of CPUs) */
min_catch = min(ilog2(ncpu), 4);
/* Initialize balancing callout and run it */
callout_init(&balance_ch, CALLOUT_MPSAFE);
callout_setfunc(&balance_ch, sched_balance, NULL);
callout_schedule(&balance_ch, balance_period);
#endif
}
void
sched_cpuattach(struct cpu_info *ci)
{
runqueue_t *ci_rq;
void *rq_ptr;
u_int i, size;
/*
* Allocate the run queue.
* XXX: Estimate cache behaviour more..
*/
size = roundup(sizeof(runqueue_t), CACHE_LINE_SIZE) + CACHE_LINE_SIZE;
rq_ptr = kmem_zalloc(size, KM_NOSLEEP);
if (rq_ptr == NULL) {
panic("scheduler: could not allocate the runqueue");
}
/* XXX: Save the original pointer for future.. */
ci_rq = (void *)(roundup((intptr_t)(rq_ptr), CACHE_LINE_SIZE));
/* Initialize run queues */
mutex_init(&ci_rq->r_rq_mutex, MUTEX_DEFAULT, IPL_SCHED);
for (i = 0; i < PRI_RT_COUNT; i++)
TAILQ_INIT(&ci_rq->r_rt_queue[i].q_head);
for (i = 0; i < PRI_TS_COUNT; i++)
TAILQ_INIT(&ci_rq->r_ts_queue[i].q_head);
ci_rq->r_highest_pri = 0;
ci->ci_schedstate.spc_sched_info = ci_rq;
ci->ci_schedstate.spc_mutex = &ci_rq->r_rq_mutex;
}
/* Pre-calculate the time-slices for the priorities */
static void
sched_precalcts(void)
{
pri_t p;
/* Time-sharing range */
for (p = 0; p <= PRI_HIGHEST_TS; p++) {
ts_map[p] = max_ts -
(p * 100 / (PRI_TS_COUNT - 1) * (max_ts - min_ts) / 100);
high_pri[p] = (PRI_HIGHEST_TS - PRI_HTS_RANGE) +
((p * PRI_HTS_RANGE) / (PRI_TS_COUNT - 1));
}
/* Real-time range */
for (p = (PRI_HIGHEST_TS + 1); p < PRI_COUNT; p++) {
ts_map[p] = rt_ts;
high_pri[p] = p;
}
}
/*
* Hooks.
*/
void
sched_proc_fork(struct proc *parent, struct proc *child)
{
struct lwp *l;
LIST_FOREACH(l, &child->p_lwps, l_sibling) {
lwp_lock(l);
sched_newts(l);
lwp_unlock(l);
}
}
void
sched_proc_exit(struct proc *child, struct proc *parent)
{
/* Dummy */
}
void
sched_lwp_fork(struct lwp *l1, struct lwp *l2)
{
KASSERT(l2->l_sched_info == NULL);
l2->l_sched_info = pool_get(&sil_pool, PR_WAITOK);
memset(l2->l_sched_info, 0, sizeof(sched_info_lwp_t));
if (l2->l_priority <= PRI_HIGHEST_TS) /* XXX: For now only.. */
l2->l_priority = PRI_DEFAULT;
}
void
sched_lwp_exit(struct lwp *l)
{
KASSERT(l->l_sched_info != NULL);
pool_put(&sil_pool, l->l_sched_info);
l->l_sched_info = NULL;
}
void
sched_lwp_collect(struct lwp *l)
{
}
void
sched_setrunnable(struct lwp *l)
{
/* Dummy */
}
void
sched_schedclock(struct lwp *l)
{
/* Dummy */
}
/*
* Priorities and time-slice.
*/
void
sched_nice(struct proc *p, int prio)
{
int nprio;
struct lwp *l;
KASSERT(mutex_owned(&p->p_smutex));
p->p_nice = prio;
nprio = max(min(PRI_DEFAULT + p->p_nice, PRI_HIGHEST_TS), 0);
LIST_FOREACH(l, &p->p_lwps, l_sibling) {
lwp_lock(l);
lwp_changepri(l, nprio);
lwp_unlock(l);
}
}
/* Recalculate the time-slice */
static inline void
sched_newts(struct lwp *l)
{
sched_info_lwp_t *sil = l->l_sched_info;
sil->sl_timeslice = ts_map[lwp_eprio(l)];
}
/*
* Control of the runqueue.
*/
static inline void *
sched_getrq(runqueue_t *ci_rq, const pri_t prio)
{
KASSERT(prio < PRI_COUNT);
return (prio <= PRI_HIGHEST_TS) ?
&ci_rq->r_ts_queue[prio].q_head :
&ci_rq->r_rt_queue[prio - PRI_HIGHEST_TS - 1].q_head;
}
void
sched_enqueue(struct lwp *l, bool swtch)
{
runqueue_t *ci_rq;
sched_info_lwp_t *sil = l->l_sched_info;
TAILQ_HEAD(, lwp) *q_head;
const pri_t eprio = lwp_eprio(l);
ci_rq = l->l_cpu->ci_schedstate.spc_sched_info;
KASSERT(lwp_locked(l, l->l_cpu->ci_schedstate.spc_mutex));
/* Update the last run time on switch */
if (__predict_true(swtch == true)) {
sil->sl_lrtime = hardclock_ticks;
sil->sl_rtsum += (hardclock_ticks - sil->sl_rtime);
} else if (sil->sl_lrtime == 0)
sil->sl_lrtime = hardclock_ticks;
/* Enqueue the thread */
q_head = sched_getrq(ci_rq, eprio);
if (TAILQ_EMPTY(q_head)) {
u_int i;
uint32_t q;
/* Mark bit */
i = eprio >> BITMAP_SHIFT;
q = BITMAP_MSB >> (eprio & BITMAP_MASK);
KASSERT((ci_rq->r_bitmap[i] & q) == 0);
ci_rq->r_bitmap[i] |= q;
}
TAILQ_INSERT_TAIL(q_head, l, l_runq);
ci_rq->r_count++;
if ((l->l_flag & LW_BOUND) == 0)
ci_rq->r_mcount++;
/*
* Update the value of highest priority in the runqueue,
* if priority of this thread is higher.
*/
if (eprio > ci_rq->r_highest_pri)
ci_rq->r_highest_pri = eprio;
sched_newts(l);
}
void
sched_dequeue(struct lwp *l)
{
runqueue_t *ci_rq;
TAILQ_HEAD(, lwp) *q_head;
const pri_t eprio = lwp_eprio(l);
ci_rq = l->l_cpu->ci_schedstate.spc_sched_info;
KASSERT(lwp_locked(l, l->l_cpu->ci_schedstate.spc_mutex));
KASSERT(eprio <= ci_rq->r_highest_pri);
KASSERT(ci_rq->r_bitmap[eprio >> BITMAP_SHIFT] != 0);
KASSERT(ci_rq->r_count > 0);
ci_rq->r_count--;
if ((l->l_flag & LW_BOUND) == 0)
ci_rq->r_mcount--;
q_head = sched_getrq(ci_rq, eprio);
TAILQ_REMOVE(q_head, l, l_runq);
if (TAILQ_EMPTY(q_head)) {
u_int i;
uint32_t q;
/* Unmark bit */
i = eprio >> BITMAP_SHIFT;
q = BITMAP_MSB >> (eprio & BITMAP_MASK);
KASSERT((ci_rq->r_bitmap[i] & q) != 0);
ci_rq->r_bitmap[i] &= ~q;
/*
* Update the value of highest priority in the runqueue, in a
* case it was a last thread in the queue of highest priority.
*/
if (eprio != ci_rq->r_highest_pri)
return;
do {
q = ffs(ci_rq->r_bitmap[i]);
if (q) {
ci_rq->r_highest_pri =
(i << BITMAP_SHIFT) + (BITMAP_BITS - q);
return;
}
} while (i--);
/* If not found - set the lowest value */
ci_rq->r_highest_pri = 0;
}
}
void
sched_slept(struct lwp *l)
{
sched_info_lwp_t *sil = l->l_sched_info;
/* Save the time when thread has slept */
sil->sl_slept = hardclock_ticks;
/*
* If thread is in time-sharing queue and batch flag is not marked,
* increase the the priority, and run with the lower time-quantum.
*/
if (l->l_priority < PRI_HIGHEST_TS && (sil->sl_flags & SL_BATCH) == 0) {
KASSERT(l->l_class == SCHED_OTHER);
l->l_priority++;
}
}
void
sched_wakeup(struct lwp *l)
{
sched_info_lwp_t *sil = l->l_sched_info;
/* Update sleep time delta */
sil->sl_slpsum += (l->l_slptime == 0) ?
(hardclock_ticks - sil->sl_slept) : hz;
/* If thread was sleeping a second or more - set a high priority */
if (l->l_slptime > 1 || (hardclock_ticks - sil->sl_slept) >= hz)
l->l_priority = high_pri[l->l_priority];
/* Also, consider looking for a better CPU to wake up */
if ((l->l_flag & (LW_BOUND | LW_SYSTEM)) == 0)
l->l_cpu = sched_takecpu(l);
}
void
sched_pstats_hook(struct lwp *l)
{
sched_info_lwp_t *sil = l->l_sched_info;
pri_t prio;
bool batch;
if (l->l_stat == LSSLEEP || l->l_stat == LSSTOP ||
l->l_stat == LSSUSPENDED)
l->l_slptime++;
/*
* Set that thread is more CPU-bound, if sum of run time exceeds the
* sum of sleep time. Check if thread is CPU-bound a first time.
*/
batch = (sil->sl_rtsum > sil->sl_slpsum);
if (batch) {
if ((sil->sl_flags & SL_BATCH) == 0)
batch = false;
sil->sl_flags |= SL_BATCH;
} else
sil->sl_flags &= ~SL_BATCH;
/* Reset the time sums */
sil->sl_slpsum = 0;
sil->sl_rtsum = 0;
/* Estimate threads on time-sharing queue only */
if (l->l_priority >= PRI_HIGHEST_TS)
return;
/* If it is CPU-bound not a first time - decrease the priority */
prio = l->l_priority;
if (batch && prio != 0)
prio--;
/* If thread was not ran a second or more - set a high priority */
if (l->l_stat == LSRUN) {
if (sil->sl_lrtime && (hardclock_ticks - sil->sl_lrtime >= hz))
prio = high_pri[prio];
/* Re-enqueue the thread if priority has changed */
if (prio != l->l_priority)
lwp_changepri(l, prio);
} else {
/* In other states, change the priority directly */
l->l_priority = prio;
}
}
/*
* Migration and balancing.
*/
#ifdef MULTIPROCESSOR
/* Check if LWP can migrate to the chosen CPU */
static inline bool
sched_migratable(const struct lwp *l, const struct cpu_info *ci)
{
if (ci->ci_schedstate.spc_flags & SPCF_OFFLINE)
return false;
if ((l->l_flag & LW_BOUND) == 0)
return true;
#if 0
return cpu_in_pset(ci, l->l_psid);
#else
return false;
#endif
}
/*
* Estimate the migration of LWP to the other CPU.
* Take and return the CPU, if migration is needed.
*/
struct cpu_info *
sched_takecpu(struct lwp *l)
{
struct cpu_info *ci, *tci = NULL;
struct schedstate_percpu *spc;
runqueue_t *ci_rq;
sched_info_lwp_t *sil;
CPU_INFO_ITERATOR cii;
pri_t eprio, lpri;
ci = l->l_cpu;
spc = &ci->ci_schedstate;
ci_rq = spc->spc_sched_info;
/* CPU of this thread is idling - run there */
if (ci_rq->r_count == 0)
return ci;
eprio = lwp_eprio(l);
sil = l->l_sched_info;
/* Stay if thread is cache-hot */
if (l->l_stat == LSSLEEP && l->l_slptime <= 1 &&
CACHE_HOT(sil) && eprio >= spc->spc_curpriority)
return ci;
/* Run on current CPU if priority of thread is higher */
ci = curcpu();
spc = &ci->ci_schedstate;
if (eprio > spc->spc_curpriority && sched_migratable(l, ci))
return ci;
/*
* Look for the CPU with the lowest priority thread. In case of
* equal the priority - check the lower count of the threads.
*/
lpri = PRI_COUNT;
for (CPU_INFO_FOREACH(cii, ci)) {
runqueue_t *ici_rq;
pri_t pri;
spc = &ci->ci_schedstate;
ici_rq = spc->spc_sched_info;
pri = max(spc->spc_curpriority, ici_rq->r_highest_pri);
if (pri > lpri)
continue;
if (pri == lpri && tci && ci_rq->r_count < ici_rq->r_count)
continue;
if (sched_migratable(l, ci) == false)
continue;
lpri = pri;
tci = ci;
ci_rq = ici_rq;
}
KASSERT(tci != NULL);
return tci;
}
/*
* Tries to catch an LWP from the runqueue of other CPU.
*/
static struct lwp *
sched_catchlwp(void)
{
struct cpu_info *curci = curcpu(), *ci = worker_ci;
TAILQ_HEAD(, lwp) *q_head;
runqueue_t *ci_rq;
struct lwp *l;
if (curci == ci)
return NULL;
/* Lockless check */
ci_rq = ci->ci_schedstate.spc_sched_info;
if (ci_rq->r_count < min_catch)
return NULL;
/*
* Double-lock the runqueues.
*/
if (curci < ci) {
spc_lock(ci);
} else if (!mutex_tryenter(ci->ci_schedstate.spc_mutex)) {
const runqueue_t *cur_rq = curci->ci_schedstate.spc_sched_info;
spc_unlock(curci);
spc_lock(ci);
spc_lock(curci);
if (cur_rq->r_count) {
spc_unlock(ci);
return NULL;
}
}
if (ci_rq->r_count < min_catch) {
spc_unlock(ci);
return NULL;
}
/* Take the highest priority thread */
q_head = sched_getrq(ci_rq, ci_rq->r_highest_pri);
l = TAILQ_FIRST(q_head);
for (;;) {
sched_info_lwp_t *sil;
/* Check the first and next result from the queue */
if (l == NULL)
break;
/* Look for threads, whose are allowed to migrate */
sil = l->l_sched_info;
if ((l->l_flag & LW_SYSTEM) || CACHE_HOT(sil) ||
sched_migratable(l, curci) == false) {
l = TAILQ_NEXT(l, l_runq);
continue;
}
/* Recheck if chosen thread is still on the runqueue */
if (l->l_stat == LSRUN && (l->l_flag & LW_INMEM)) {
sched_dequeue(l);
l->l_cpu = curci;
lwp_setlock(l, curci->ci_schedstate.spc_mutex);
sched_enqueue(l, false);
break;
}
l = TAILQ_NEXT(l, l_runq);
}
spc_unlock(ci);
return l;
}
/*
* Periodical calculations for balancing.
*/
static void
sched_balance(void *nocallout)
{
struct cpu_info *ci, *hci;
runqueue_t *ci_rq;
CPU_INFO_ITERATOR cii;
u_int highest;
hci = curcpu();
highest = 0;
/* Make lockless countings */
for (CPU_INFO_FOREACH(cii, ci)) {
ci_rq = ci->ci_schedstate.spc_sched_info;
/* Average count of the threads */
ci_rq->r_avgcount = (ci_rq->r_avgcount + ci_rq->r_mcount) >> 1;
/* Look for CPU with the highest average */
if (ci_rq->r_avgcount > highest) {
hci = ci;
highest = ci_rq->r_avgcount;
}
}
/* Update the worker */
worker_ci = hci;
if (nocallout == NULL)
callout_schedule(&balance_ch, balance_period);
}
#else
struct cpu_info *
sched_takecpu(struct lwp *l)
{
return l->l_cpu;
}
#endif /* MULTIPROCESSOR */
/*
* Scheduler mill.
*/
struct lwp *
sched_nextlwp(void)
{
struct cpu_info *ci = curcpu();
struct schedstate_percpu *spc;
TAILQ_HEAD(, lwp) *q_head;
sched_info_lwp_t *sil;
runqueue_t *ci_rq;
struct lwp *l;
spc = &ci->ci_schedstate;
ci_rq = ci->ci_schedstate.spc_sched_info;
#ifdef MULTIPROCESSOR
/* If runqueue is empty, try to catch some thread from other CPU */
if (__predict_false(spc->spc_flags & SPCF_OFFLINE)) {
if ((ci_rq->r_count - ci_rq->r_mcount) == 0)
return NULL;
} else if (ci_rq->r_count == 0) {
/* Reset the counter, and call the balancer */
ci_rq->r_avgcount = 0;
sched_balance(ci);
/* The re-locking will be done inside */
return sched_catchlwp();
}
#else
if (ci_rq->r_count == 0)
return NULL;
#endif
/* Take the highest priority thread */
KASSERT(ci_rq->r_bitmap[ci_rq->r_highest_pri >> BITMAP_SHIFT]);
q_head = sched_getrq(ci_rq, ci_rq->r_highest_pri);
l = TAILQ_FIRST(q_head);
KASSERT(l != NULL);
/* Update the counters */
sil = l->l_sched_info;
KASSERT(sil->sl_timeslice >= min_ts);
KASSERT(sil->sl_timeslice <= max_ts);
spc->spc_ticks = sil->sl_timeslice;
sil->sl_rtime = hardclock_ticks;
return l;
}
bool
sched_curcpu_runnable_p(void)
{
const struct cpu_info *ci = curcpu();
const runqueue_t *ci_rq = ci->ci_schedstate.spc_sched_info;
#ifndef __HAVE_FAST_SOFTINTS
if (ci->ci_data.cpu_softints)
return true;
#endif
if (ci->ci_schedstate.spc_flags & SPCF_OFFLINE)
return (ci_rq->r_count - ci_rq->r_mcount);
return ci_rq->r_count;
}
/*
* Time-driven events.
*/
/*
* Called once per time-quantum. This routine is CPU-local and runs at
* IPL_SCHED, thus the locking is not needed.
*/
void
sched_tick(struct cpu_info *ci)
{
const runqueue_t *ci_rq = ci->ci_schedstate.spc_sched_info;
struct schedstate_percpu *spc = &ci->ci_schedstate;
struct lwp *l = curlwp;
sched_info_lwp_t *sil = l->l_sched_info;
if (CURCPU_IDLE_P())
return;
switch (l->l_class) {
case SCHED_FIFO:
/*
* Update the time-quantum, and continue running,
* if thread runs on FIFO real-time policy.
*/
spc->spc_ticks = sil->sl_timeslice;
return;
case SCHED_OTHER:
/*
* If thread is in time-sharing queue, decrease the priority,
* and run with a higher time-quantum.
*/
if (l->l_priority > PRI_HIGHEST_TS)
break;
if (l->l_priority != 0)
l->l_priority--;
break;
}
/*
* If there are higher priority threads or threads in the same queue,
* mark that thread should yield, otherwise, continue running.
*/
if (lwp_eprio(l) <= ci_rq->r_highest_pri) {
spc->spc_flags |= SPCF_SHOULDYIELD;
cpu_need_resched(ci, 0);
} else
spc->spc_ticks = sil->sl_timeslice;
}
/*
* Sysctl nodes and initialization.
*/
static int
sysctl_sched_mints(SYSCTLFN_ARGS)
{
struct sysctlnode node;
struct cpu_info *ci;
int error, newsize;
CPU_INFO_ITERATOR cii;
node = *rnode;
node.sysctl_data = &newsize;
newsize = hztoms(min_ts);
error = sysctl_lookup(SYSCTLFN_CALL(&node));
if (error || newp == NULL)
return error;
newsize = mstohz(newsize);
if (newsize < 1 || newsize > hz || newsize >= max_ts)
return EINVAL;
/* It is safe to do this in such order */
for (CPU_INFO_FOREACH(cii, ci))
spc_lock(ci);
min_ts = newsize;
sched_precalcts();
for (CPU_INFO_FOREACH(cii, ci))
spc_unlock(ci);
return 0;
}
static int
sysctl_sched_maxts(SYSCTLFN_ARGS)
{
struct sysctlnode node;
struct cpu_info *ci;
int error, newsize;
CPU_INFO_ITERATOR cii;
node = *rnode;
node.sysctl_data = &newsize;
newsize = hztoms(max_ts);
error = sysctl_lookup(SYSCTLFN_CALL(&node));
if (error || newp == NULL)
return error;
newsize = mstohz(newsize);
if (newsize < 10 || newsize > hz || newsize <= min_ts)
return EINVAL;
/* It is safe to do this in such order */
for (CPU_INFO_FOREACH(cii, ci))
spc_lock(ci);
max_ts = newsize;
sched_precalcts();
for (CPU_INFO_FOREACH(cii, ci))
spc_unlock(ci);
return 0;
}
SYSCTL_SETUP(sysctl_sched_setup, "sysctl kern.sched subtree setup")
{
const struct sysctlnode *node = NULL;
sysctl_createv(clog, 0, NULL, NULL,
CTLFLAG_PERMANENT,
CTLTYPE_NODE, "kern", NULL,
NULL, 0, NULL, 0,
CTL_KERN, CTL_EOL);
sysctl_createv(clog, 0, NULL, &node,
CTLFLAG_PERMANENT,
CTLTYPE_NODE, "sched",
SYSCTL_DESCR("Scheduler options"),
NULL, 0, NULL, 0,
CTL_KERN, CTL_CREATE, CTL_EOL);
if (node == NULL)
return;
sysctl_createv(clog, 0, &node, NULL,
CTLFLAG_PERMANENT,
CTLTYPE_STRING, "name", NULL,
NULL, 0, __UNCONST("M2"), 0,
CTL_CREATE, CTL_EOL);
sysctl_createv(clog, 0, &node, NULL,
CTLFLAG_PERMANENT | CTLFLAG_READWRITE,
CTLTYPE_INT, "maxts",
SYSCTL_DESCR("Maximal time quantum (in miliseconds)"),
sysctl_sched_maxts, 0, &max_ts, 0,
CTL_CREATE, CTL_EOL);
sysctl_createv(clog, 0, &node, NULL,
CTLFLAG_PERMANENT | CTLFLAG_READWRITE,
CTLTYPE_INT, "mints",
SYSCTL_DESCR("Minimal time quantum (in miliseconds)"),
sysctl_sched_mints, 0, &min_ts, 0,
CTL_CREATE, CTL_EOL);
#ifdef MULTIPROCESSOR
sysctl_createv(clog, 0, &node, NULL,
CTLFLAG_PERMANENT | CTLFLAG_READWRITE,
CTLTYPE_INT, "cacheht_time",
SYSCTL_DESCR("Cache hotness time (in ticks)"),
NULL, 0, &cacheht_time, 0,
CTL_CREATE, CTL_EOL);
sysctl_createv(clog, 0, &node, NULL,
CTLFLAG_PERMANENT | CTLFLAG_READWRITE,
CTLTYPE_INT, "balance_period",
SYSCTL_DESCR("Balance period (in ticks)"),
NULL, 0, &balance_period, 0,
CTL_CREATE, CTL_EOL);
sysctl_createv(clog, 0, &node, NULL,
CTLFLAG_PERMANENT | CTLFLAG_READWRITE,
CTLTYPE_INT, "min_catch",
SYSCTL_DESCR("Minimal count of the threads for catching"),
NULL, 0, &min_catch, 0,
CTL_CREATE, CTL_EOL);
#endif
}
/*
* Debugging.
*/
#ifdef DDB
void
sched_print_runqueue(void (*pr)(const char *, ...))
{
runqueue_t *ci_rq;
sched_info_lwp_t *sil;
struct lwp *l;
struct proc *p;
int i;
struct cpu_info *ci;
CPU_INFO_ITERATOR cii;
for (CPU_INFO_FOREACH(cii, ci)) {
ci_rq = ci->ci_schedstate.spc_sched_info;
(*pr)("Run-queue (CPU = %d):\n", ci->ci_cpuid);
(*pr)(" pid.lid = %d.%d, threads count = %u, "
"avgcount = %u, highest pri = %d\n",
ci->ci_curlwp->l_proc->p_pid, ci->ci_curlwp->l_lid,
ci_rq->r_count, ci_rq->r_avgcount, ci_rq->r_highest_pri);
i = (PRI_COUNT >> BITMAP_SHIFT) - 1;
do {
uint32_t q;
q = ci_rq->r_bitmap[i];
(*pr)(" bitmap[%d] => [ %d (0x%x) ]\n", i, ffs(q), q);
} while (i--);
}
(*pr)(" %5s %4s %4s %10s %3s %4s %11s %3s %s\n",
"LID", "PRI", "EPRI", "FL", "ST", "TS", "LWP", "CPU", "LRTIME");
PROCLIST_FOREACH(p, &allproc) {
(*pr)(" /- %d (%s)\n", (int)p->p_pid, p->p_comm);
LIST_FOREACH(l, &p->p_lwps, l_sibling) {
sil = l->l_sched_info;
ci = l->l_cpu;
(*pr)(" | %5d %4u %4u 0x%8.8x %3s %4u %11p %3d "
"%u ST=%d RT=%d %d\n",
(int)l->l_lid, l->l_priority, lwp_eprio(l),
l->l_flag, l->l_stat == LSRUN ? "RQ" :
(l->l_stat == LSSLEEP ? "SQ" : "-"),
sil->sl_timeslice, l, ci->ci_cpuid,
(u_int)(hardclock_ticks - sil->sl_lrtime),
sil->sl_slpsum, sil->sl_rtsum, sil->sl_flags);
}
}
}
#endif /* defined(DDB) */
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