d/freebsd-dev
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

- Create a new scheduler api that is defined in sys/sched.h

Browse Source 
- Begin moving scheduler specific functionality into sched_4bsd.c
 - Replace direct manipulation of scheduler data with hooks provided by the
   new api.
 - Remove KSE specific state modifications and single runq assumptions from
   kern_switch.c

Reviewed by:	-arch
This commit is contained in:
Jeff Roberson 2002-10-12 05:32:24 +00:00
parent bd26dcd103
commit b43179fbe8
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=104964
21 changed files with 774 additions and 528 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
sys/amd64/amd64/machdep.c
View File

@ -69,6 +69,7 @@
#include <sys/reboot.h>
#include <sys/callout.h>
#include <sys/msgbuf.h>
#include <sys/sched.h>
#include <sys/sysent.h>
#include <sys/sysctl.h>
#include <sys/ucontext.h>
@ -818,7 +819,7 @@ SYSCTL_INT(_machdep, OID_AUTO, cpu_idle_hlt, CTLFLAG_RW,
/*
* Note that we have to be careful here to avoid a race between checking
* kserunnable() and actually halting. If we don't do this, we may waste
* sched_runnable() and actually halting. If we don't do this, we may waste
* the time between calling hlt and the next interrupt even though there
* is a runnable process.
*/
@ -827,7 +828,7 @@ cpu_idle(void)
{
if (cpu_idle_hlt) {
disable_intr();
if (kserunnable()) {
if (sched_runnable()) {
enable_intr();
} else {
/*

1
sys/conf/files
View File

@ -946,6 +946,7 @@ kern/kern_uuid.c standard
kern/kern_xxx.c standard
kern/link_elf.c standard
kern/md5c.c standard
kern/sched_4bsd.c standard
kern/subr_autoconf.c standard
kern/subr_blist.c standard
kern/subr_bus.c standard

5
sys/i386/i386/machdep.c
View File

@ -69,6 +69,7 @@
#include <sys/reboot.h>
#include <sys/callout.h>
#include <sys/msgbuf.h>
#include <sys/sched.h>
#include <sys/sysent.h>
#include <sys/sysctl.h>
#include <sys/ucontext.h>
@ -818,7 +819,7 @@ SYSCTL_INT(_machdep, OID_AUTO, cpu_idle_hlt, CTLFLAG_RW,
/*
* Note that we have to be careful here to avoid a race between checking
* kserunnable() and actually halting. If we don't do this, we may waste
* sched_runnable() and actually halting. If we don't do this, we may waste
* the time between calling hlt and the next interrupt even though there
* is a runnable process.
*/
@ -827,7 +828,7 @@ cpu_idle(void)
{
if (cpu_idle_hlt) {
disable_intr();
if (kserunnable()) {
if (sched_runnable()) {
enable_intr();
} else {
/*

3
sys/kern/kern_clock.c
View File

@ -51,6 +51,7 @@
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/resourcevar.h>
#include <sys/sched.h>
#include <sys/signalvar.h>
#include <sys/smp.h>
#include <vm/vm.h>
@ -437,7 +438,7 @@ statclock_process(ke, pc, user)
}
}
schedclock(ke->ke_thread);
sched_clock(ke->ke_thread);
/* Update resource usage integrals and maximums. */
if ((pstats = p->p_stats) != NULL &&

17
sys/kern/kern_exit.c
View File

@ -57,6 +57,7 @@
#include <sys/vnode.h>
#include <sys/resourcevar.h>
#include <sys/signalvar.h>
#include <sys/sched.h>
#include <sys/sx.h>
#include <sys/ptrace.h>
#include <sys/acct.h> /* for acct_process() function prototype */
@ -605,21 +606,13 @@ wait1(td, uap, compat)
nfound++;
if (p->p_state == PRS_ZOMBIE) {
/*
* charge childs scheduling cpu usage to parent
* XXXKSE assume only one thread & kse & ksegrp
* keep estcpu in each ksegrp
* so charge it to the ksegrp that did the wait
* since process estcpu is sum of all ksegrps,
* this is strictly as expected.
* Assume that the child process aggregated all
* tke estcpu into the 'build-in' ksegrp.
* XXXKSE
* Allow the scheduler to adjust the priority of the
* parent when a kseg is exiting.
*/
if (curthread->td_proc->p_pid != 1) {
mtx_lock_spin(&sched_lock);
curthread->td_ksegrp->kg_estcpu =
ESTCPULIM(curthread->td_ksegrp->kg_estcpu +
FIRST_KSEGRP_IN_PROC(p)->kg_estcpu);
sched_exit(curthread->td_ksegrp,
FIRST_KSEGRP_IN_PROC(p));
mtx_unlock_spin(&sched_lock);
}

13
sys/kern/kern_fork.c
View File

@ -53,6 +53,7 @@
#include <sys/proc.h>
#include <sys/pioctl.h>
#include <sys/resourcevar.h>
#include <sys/sched.h>
#include <sys/syscall.h>
#include <sys/vnode.h>
#include <sys/acct.h>
@ -515,6 +516,12 @@ fork1(td, flags, pages, procp)
p2->p_sflag = PS_INMEM;
if (p1->p_sflag & PS_PROFIL)
startprofclock(p2);
/*
* Allow the scheduler to adjust the priority of the child and
* parent while we hold the sched_lock.
*/
sched_fork(td->td_ksegrp, kg2);
mtx_unlock_spin(&sched_lock);
p2->p_ucred = crhold(td->td_ucred);
td2->td_ucred = crhold(p2->p_ucred); /* XXXKSE */
@ -634,12 +641,6 @@ fork1(td, flags, pages, procp)
p2->p_pfsflags = p1->p_pfsflags;
}
/*
* set priority of child to be that of parent.
* XXXKSE this needs redefining..
*/
kg2->kg_estcpu = td->td_ksegrp->kg_estcpu;
/*
* This begins the section where we must prevent the parent
* from being swapped.

5
sys/kern/kern_idle.c
View File

@ -16,6 +16,7 @@
#include <sys/pcpu.h>
#include <sys/proc.h>
#include <sys/resourcevar.h>
#include <sys/sched.h>
#include <sys/smp.h>
#include <sys/unistd.h>
#ifdef KTRACE
@ -90,9 +91,9 @@ idle_proc(void *dummy)
#ifdef DIAGNOSTIC
count = 0;
while (count >= 0 && kserunnable() == 0) {
while (count >= 0 && sched_runnable() == 0) {
#else
while (kserunnable() == 0) {
while (sched_runnable() == 0) {
#endif
/*
* This is a good place to put things to be done in

6
sys/kern/kern_mutex.c
View File

@ -47,6 +47,7 @@
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/resourcevar.h>
#include <sys/sched.h>
#include <sys/sbuf.h>
#include <sys/stdint.h>
#include <sys/sysctl.h>
@ -146,13 +147,10 @@ propagate_priority(struct thread *td)
* If on run queue move to new run queue, and quit.
* XXXKSE this gets a lot more complicated under threads
* but try anyhow.
* We should have a special call to do this more efficiently.
*/
if (TD_ON_RUNQ(td)) {
MPASS(td->td_blocked == NULL);
remrunqueue(td);
td->td_priority = pri;
setrunqueue(td);
sched_prio(td, pri);
return;
}
/*

4
sys/kern/kern_resource.c
View File

@ -51,6 +51,7 @@
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/resourcevar.h>
#include <sys/sched.h>
#include <sys/sx.h>
#include <sys/sysent.h>
#include <sys/time.h>
@ -295,8 +296,7 @@ donice(struct thread *td, struct proc *p, int n)
if (n < low && suser(td))
return (EACCES);
FOREACH_KSEGRP_IN_PROC(p, kg) {
kg->kg_nice = n;
(void)resetpriority(kg);
sched_nice(kg, n);
}
return (0);
}

3
sys/kern/kern_subr.c
View File

@ -50,6 +50,7 @@
#include <sys/proc.h>
#include <sys/malloc.h>
#include <sys/resourcevar.h>
#include <sys/sched.h>
#include <sys/sysctl.h>
#include <sys/vnode.h>
@ -554,7 +555,7 @@ uio_yield()
td = curthread;
mtx_lock_spin(&sched_lock);
DROP_GIANT();
td->td_priority = td->td_ksegrp->kg_user_pri; /* XXXKSE */
sched_prio(td, td->td_ksegrp->kg_user_pri); /* XXXKSE */
td->td_proc->p_stats->p_ru.ru_nivcsw++;
mi_switch();
mtx_unlock_spin(&sched_lock);

60
sys/kern/kern_switch.c
View File

@ -97,16 +97,11 @@ reassigned to keep this true.
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/queue.h>
#include <sys/sched.h>
#include <machine/critical.h>
CTASSERT((RQB_BPW * RQB_LEN) == RQ_NQS);
/*
* Global run queue.
*/
static struct runq runq;
SYSINIT(runq, SI_SUB_RUN_QUEUE, SI_ORDER_FIRST, runq_init, &runq)
void panc(char *string1, char *string2);
#if 0
@ -129,7 +124,7 @@ choosethread(void)
struct ksegrp *kg;
retry:
if ((ke = runq_choose(&runq))) {
if ((ke = sched_choose())) {
td = ke->ke_thread;
KASSERT((td->td_kse == ke), ("kse/thread mismatch"));
kg = ke->ke_ksegrp;
@ -228,7 +223,7 @@ kse_reassign(struct kse *ke)
kg->kg_last_assigned = td;
td->td_kse = ke;
ke->ke_thread = td;
runq_add(&runq, ke);
sched_add(ke);
/*
* if we have already borrowed this,
* just pass it to the new thread,
@ -282,12 +277,6 @@ kse_reassign(struct kse *ke)
CTR1(KTR_RUNQ, "kse_reassign: ke%p idled", ke);
}
int
kserunnable(void)
{
return runq_check(&runq);
}
/*
* Remove a thread from its KSEGRP's run queue.
* This in turn may remove it from a KSE if it was already assigned
@ -314,7 +303,7 @@ remrunqueue(struct thread *td)
TD_SET_CAN_RUN(td);
if ((td->td_flags & TDF_UNBOUND) == 0) {
/* Bring its kse with it, leave the thread attached */
runq_remove(&runq, ke);
sched_rem(ke);
ke->ke_state = KES_THREAD;
return;
}
@ -358,7 +347,7 @@ setrunqueue(struct thread *td)
* and the KSE is always already attached.
* Totally ignore the ksegrp run queue.
*/
runq_add(&runq, td->td_kse);
sched_add(td->td_kse);
return;
}
if ((td->td_flags & TDF_UNBOUND) == 0) {
@ -371,7 +360,7 @@ setrunqueue(struct thread *td)
TAILQ_REMOVE(&kg->kg_lq, ke, ke_kgrlist);
kg->kg_loan_kses--;
}
runq_add(&runq, td->td_kse);
sched_add(td->td_kse);
return;
}
@ -416,7 +405,7 @@ setrunqueue(struct thread *td)
ke->ke_thread = NULL;
tda = kg->kg_last_assigned =
TAILQ_PREV(tda, threadqueue, td_runq);
runq_remove(&runq, ke);
sched_rem(ke);
}
} else {
/*
@ -475,7 +464,7 @@ setrunqueue(struct thread *td)
td2->td_kse = ke;
ke->ke_thread = td2;
}
runq_add(&runq, ke);
sched_add(ke);
}
}
@ -592,15 +581,6 @@ runq_add(struct runq *rq, struct kse *ke)
struct rqhead *rqh;
int pri;
mtx_assert(&sched_lock, MA_OWNED);
KASSERT((ke->ke_thread != NULL), ("runq_add: No thread on KSE"));
KASSERT((ke->ke_thread->td_kse != NULL),
("runq_add: No KSE on thread"));
KASSERT(ke->ke_state != KES_ONRUNQ,
("runq_add: kse %p (%s) already in run queue", ke,
ke->ke_proc->p_comm));
KASSERT(ke->ke_proc->p_sflag & PS_INMEM,
("runq_add: process swapped out"));
pri = ke->ke_thread->td_priority / RQ_PPQ;
ke->ke_rqindex = pri;
runq_setbit(rq, pri);
@ -608,8 +588,6 @@ runq_add(struct runq *rq, struct kse *ke)
CTR4(KTR_RUNQ, "runq_add: p=%p pri=%d %d rqh=%p",
ke->ke_proc, ke->ke_thread->td_priority, pri, rqh);
TAILQ_INSERT_TAIL(rqh, ke, ke_procq);
ke->ke_ksegrp->kg_runq_kses++;
ke->ke_state = KES_ONRUNQ;
}
/*
@ -636,9 +614,7 @@ runq_check(struct runq *rq)
}
/*
* Find and remove the highest priority process from the run queue.
* If there are no runnable processes, the per-cpu idle process is
* returned. Will not return NULL under any circumstances.
* Find the highest priority process on the run queue.
*/
struct kse *
runq_choose(struct runq *rq)
@ -654,20 +630,6 @@ runq_choose(struct runq *rq)
KASSERT(ke != NULL, ("runq_choose: no proc on busy queue"));
CTR3(KTR_RUNQ,
"runq_choose: pri=%d kse=%p rqh=%p", pri, ke, rqh);
TAILQ_REMOVE(rqh, ke, ke_procq);
ke->ke_ksegrp->kg_runq_kses--;
if (TAILQ_EMPTY(rqh)) {
CTR0(KTR_RUNQ, "runq_choose: empty");
runq_clrbit(rq, pri);
}
ke->ke_state = KES_THREAD;
KASSERT((ke->ke_thread != NULL),
("runq_choose: No thread on KSE"));
KASSERT((ke->ke_thread->td_kse != NULL),
("runq_choose: No KSE on thread"));
KASSERT(ke->ke_proc->p_sflag & PS_INMEM,
("runq_choose: process swapped out"));
return (ke);
}
CTR1(KTR_RUNQ, "runq_choose: idleproc pri=%d", pri);
@ -686,8 +648,6 @@ runq_remove(struct runq *rq, struct kse *ke)
struct rqhead *rqh;
int pri;
KASSERT((ke->ke_state == KES_ONRUNQ), ("KSE not on run queue"));
mtx_assert(&sched_lock, MA_OWNED);
KASSERT(ke->ke_proc->p_sflag & PS_INMEM,
("runq_remove: process swapped out"));
pri = ke->ke_rqindex;
@ -700,8 +660,6 @@ runq_remove(struct runq *rq, struct kse *ke)
CTR0(KTR_RUNQ, "runq_remove: empty");
runq_clrbit(rq, pri);
}
ke->ke_state = KES_THREAD;
ke->ke_ksegrp->kg_runq_kses--;
}
#if 0

436
sys/kern/kern_synch.c
View File

@ -51,6 +51,7 @@
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/resourcevar.h>
#include <sys/sched.h>
#include <sys/signalvar.h>
#include <sys/smp.h>
#include <sys/sx.h>
@ -72,11 +73,8 @@ SYSINIT(sched_setup, SI_SUB_KICK_SCHEDULER, SI_ORDER_FIRST, sched_setup, NULL)
int hogticks;
int lbolt;
int sched_quantum; /* Roundrobin scheduling quantum in ticks. */
static struct callout loadav_callout;
static struct callout schedcpu_callout;
static struct callout roundrobin_callout;
struct loadavg averunnable =
{ {0, 0, 0}, FSCALE }; /* load average, of runnable procs */
@ -92,316 +90,6 @@ static fixpt_t cexp[3] = {
static void endtsleep(void *);
static void loadav(void *arg);
static void roundrobin(void *arg);
static void schedcpu(void *arg);
static int
sysctl_kern_quantum(SYSCTL_HANDLER_ARGS)
{
int error, new_val;
new_val = sched_quantum * tick;
error = sysctl_handle_int(oidp, &new_val, 0, req);
if (error != 0 || req->newptr == NULL)
return (error);
if (new_val < tick)
return (EINVAL);
sched_quantum = new_val / tick;
hogticks = 2 * sched_quantum;
return (0);
}
SYSCTL_PROC(_kern, OID_AUTO, quantum, CTLTYPE_INT|CTLFLAG_RW,
0, sizeof sched_quantum, sysctl_kern_quantum, "I",
"Roundrobin scheduling quantum in microseconds");
/*
* Arrange to reschedule if necessary, taking the priorities and
* schedulers into account.
*/
void
maybe_resched(struct thread *td)
{
mtx_assert(&sched_lock, MA_OWNED);
if (td->td_priority < curthread->td_priority)
curthread->td_kse->ke_flags |= KEF_NEEDRESCHED;
}
int
roundrobin_interval(void)
{
return (sched_quantum);
}
/*
* Force switch among equal priority processes every 100ms.
* We don't actually need to force a context switch of the current process.
* The act of firing the event triggers a context switch to softclock() and
* then switching back out again which is equivalent to a preemption, thus
* no further work is needed on the local CPU.
*/
/* ARGSUSED */
static void
roundrobin(arg)
void *arg;
{
#ifdef SMP
mtx_lock_spin(&sched_lock);
forward_roundrobin();
mtx_unlock_spin(&sched_lock);
#endif
callout_reset(&roundrobin_callout, sched_quantum, roundrobin, NULL);
}
/*
* Constants for digital decay and forget:
* 90% of (p_estcpu) usage in 5 * loadav time
* 95% of (p_pctcpu) usage in 60 seconds (load insensitive)
* Note that, as ps(1) mentions, this can let percentages
* total over 100% (I've seen 137.9% for 3 processes).
*
* Note that schedclock() updates p_estcpu and p_cpticks asynchronously.
*
* We wish to decay away 90% of p_estcpu in (5 * loadavg) seconds.
* That is, the system wants to compute a value of decay such
* that the following for loop:
* for (i = 0; i < (5 * loadavg); i++)
* p_estcpu *= decay;
* will compute
* p_estcpu *= 0.1;
* for all values of loadavg:
*
* Mathematically this loop can be expressed by saying:
* decay ** (5 * loadavg) ~= .1
*
* The system computes decay as:
* decay = (2 * loadavg) / (2 * loadavg + 1)
*
* We wish to prove that the system's computation of decay
* will always fulfill the equation:
* decay ** (5 * loadavg) ~= .1
*
* If we compute b as:
* b = 2 * loadavg
* then
* decay = b / (b + 1)
*
* We now need to prove two things:
* 1) Given factor ** (5 * loadavg) ~= .1, prove factor == b/(b+1)
* 2) Given b/(b+1) ** power ~= .1, prove power == (5 * loadavg)
*
* Facts:
* For x close to zero, exp(x) =~ 1 + x, since
* exp(x) = 0! + x**1/1! + x**2/2! + ... .
* therefore exp(-1/b) =~ 1 - (1/b) = (b-1)/b.
* For x close to zero, ln(1+x) =~ x, since
* ln(1+x) = x - x**2/2 + x**3/3 - ... -1 < x < 1
* therefore ln(b/(b+1)) = ln(1 - 1/(b+1)) =~ -1/(b+1).
* ln(.1) =~ -2.30
*
* Proof of (1):
* Solve (factor)**(power) =~ .1 given power (5*loadav):
* solving for factor,
* ln(factor) =~ (-2.30/5*loadav), or
* factor =~ exp(-1/((5/2.30)*loadav)) =~ exp(-1/(2*loadav)) =
* exp(-1/b) =~ (b-1)/b =~ b/(b+1). QED
*
* Proof of (2):
* Solve (factor)**(power) =~ .1 given factor == (b/(b+1)):
* solving for power,
* power*ln(b/(b+1)) =~ -2.30, or
* power =~ 2.3 * (b + 1) = 4.6*loadav + 2.3 =~ 5*loadav. QED
*
* Actual power values for the implemented algorithm are as follows:
* loadav: 1 2 3 4
* power: 5.68 10.32 14.94 19.55
*/
/* calculations for digital decay to forget 90% of usage in 5*loadav sec */
#define loadfactor(loadav) (2 * (loadav))
#define decay_cpu(loadfac, cpu) (((loadfac) * (cpu)) / ((loadfac) + FSCALE))
/* decay 95% of `p_pctcpu' in 60 seconds; see CCPU_SHIFT before changing */
static fixpt_t ccpu = 0.95122942450071400909 * FSCALE; /* exp(-1/20) */
SYSCTL_INT(_kern, OID_AUTO, ccpu, CTLFLAG_RD, &ccpu, 0, "");
/* kernel uses `FSCALE', userland (SHOULD) use kern.fscale */
static int fscale __unused = FSCALE;
SYSCTL_INT(_kern, OID_AUTO, fscale, CTLFLAG_RD, 0, FSCALE, "");
/*
* If `ccpu' is not equal to `exp(-1/20)' and you still want to use the
* faster/more-accurate formula, you'll have to estimate CCPU_SHIFT below
* and possibly adjust FSHIFT in "param.h" so that (FSHIFT >= CCPU_SHIFT).
*
* To estimate CCPU_SHIFT for exp(-1/20), the following formula was used:
* 1 - exp(-1/20) ~= 0.0487 ~= 0.0488 == 1 (fixed pt, *11* bits).
*
* If you don't want to bother with the faster/more-accurate formula, you
* can set CCPU_SHIFT to (FSHIFT + 1) which will use a slower/less-accurate
* (more general) method of calculating the %age of CPU used by a process.
*/
#define CCPU_SHIFT 11
/*
* Recompute process priorities, every hz ticks.
* MP-safe, called without the Giant mutex.
*/
/* ARGSUSED */
static void
schedcpu(arg)
void *arg;
{
register fixpt_t loadfac = loadfactor(averunnable.ldavg[0]);
struct thread *td;
struct proc *p;
struct kse *ke;
struct ksegrp *kg;
int realstathz;
int awake;
realstathz = stathz ? stathz : hz;
sx_slock(&allproc_lock);
FOREACH_PROC_IN_SYSTEM(p) {
mtx_lock_spin(&sched_lock);
p->p_swtime++;
FOREACH_KSEGRP_IN_PROC(p, kg) {
awake = 0;
FOREACH_KSE_IN_GROUP(kg, ke) {
/*
* Increment time in/out of memory and sleep
* time (if sleeping). We ignore overflow;
* with 16-bit int's (remember them?)
* overflow takes 45 days.
*/
/*
* The kse slptimes are not touched in wakeup
* because the thread may not HAVE a KSE.
*/
if (ke->ke_state == KES_ONRUNQ) {
awake = 1;
ke->ke_flags &= ~KEF_DIDRUN;
} else if ((ke->ke_state == KES_THREAD) &&
(TD_IS_RUNNING(ke->ke_thread))) {
awake = 1;
/* Do not clear KEF_DIDRUN */
} else if (ke->ke_flags & KEF_DIDRUN) {
awake = 1;
ke->ke_flags &= ~KEF_DIDRUN;
}
/*
* pctcpu is only for ps?
* Do it per kse.. and add them up at the end?
* XXXKSE
*/
ke->ke_pctcpu
= (ke->ke_pctcpu * ccpu) >> FSHIFT;
/*
* If the kse has been idle the entire second,
* stop recalculating its priority until
* it wakes up.
*/
if (ke->ke_cpticks == 0)
continue;
#if (FSHIFT >= CCPU_SHIFT)
ke->ke_pctcpu += (realstathz == 100) ?
((fixpt_t) ke->ke_cpticks) <<
(FSHIFT - CCPU_SHIFT) :
100 * (((fixpt_t) ke->ke_cpticks) <<
(FSHIFT - CCPU_SHIFT)) / realstathz;
#else
ke->ke_pctcpu += ((FSCALE - ccpu) *
(ke->ke_cpticks * FSCALE / realstathz)) >>
FSHIFT;
#endif
ke->ke_cpticks = 0;
} /* end of kse loop */
/*
* If there are ANY running threads in this KSEGRP,
* then don't count it as sleeping.
*/
if (awake) {
if (kg->kg_slptime > 1) {
/*
* In an ideal world, this should not
* happen, because whoever woke us
* up from the long sleep should have
* unwound the slptime and reset our
* priority before we run at the stale
* priority. Should KASSERT at some
* point when all the cases are fixed.
*/
updatepri(kg);
}
kg->kg_slptime = 0;
} else {
kg->kg_slptime++;
}
if (kg->kg_slptime > 1)
continue;
kg->kg_estcpu = decay_cpu(loadfac, kg->kg_estcpu);
resetpriority(kg);
FOREACH_THREAD_IN_GROUP(kg, td) {
int changedqueue;
if (td->td_priority >= PUSER) {
/*
* Only change the priority
* of threads that are still at their
* user priority.
* XXXKSE This is problematic
* as we may need to re-order
* the threads on the KSEG list.
*/
changedqueue =
((td->td_priority / RQ_PPQ) !=
(kg->kg_user_pri / RQ_PPQ));
td->td_priority = kg->kg_user_pri;
if (changedqueue && TD_ON_RUNQ(td)) {
/* this could be optimised */
remrunqueue(td);
td->td_priority =
kg->kg_user_pri;
setrunqueue(td);
} else {
td->td_priority = kg->kg_user_pri;
}
}
}
} /* end of ksegrp loop */
mtx_unlock_spin(&sched_lock);
} /* end of process loop */
sx_sunlock(&allproc_lock);
wakeup(&lbolt);
callout_reset(&schedcpu_callout, hz, schedcpu, NULL);
}
/*
* Recalculate the priority of a process after it has slept for a while.
* For all load averages >= 1 and max p_estcpu of 255, sleeping for at
* least six times the loadfactor will decay p_estcpu to zero.
*/
void
updatepri(struct ksegrp *kg)
{
register unsigned int newcpu;
register fixpt_t loadfac = loadfactor(averunnable.ldavg[0]);
newcpu = kg->kg_estcpu;
if (kg->kg_slptime > 5 * loadfac)
kg->kg_estcpu = 0;
else {
kg->kg_slptime--; /* the first time was done in schedcpu */
while (newcpu && --kg->kg_slptime)
newcpu = decay_cpu(loadfac, newcpu);
kg->kg_estcpu = newcpu;
}
resetpriority(kg);
}
/*
* We're only looking at 7 bits of the address; everything is
@ -417,8 +105,7 @@ sleepinit(void)
{
int i;
sched_quantum = hz/10;
hogticks = 2 * sched_quantum;
hogticks = (hz / 10) * 2; /* Default only. */
for (i = 0; i < TABLESIZE; i++)
TAILQ_INIT(&slpque[i]);
}
@ -519,8 +206,6 @@ msleep(ident, mtx, priority, wmesg, timo)
td->td_wchan = ident;
td->td_wmesg = wmesg;
td->td_ksegrp->kg_slptime = 0;
td->td_priority = priority & PRIMASK;
TAILQ_INSERT_TAIL(&slpque[LOOKUP(ident)], td, td_slpq);
TD_SET_ON_SLEEPQ(td);
if (timo)
@ -551,11 +236,20 @@ msleep(ident, mtx, priority, wmesg, timo)
catch = 0;
} else
sig = 0;
/*
* Let the scheduler know we're about to voluntarily go to sleep.
*/
sched_sleep(td, priority & PRIMASK);
if (TD_ON_SLEEPQ(td)) {
p->p_stats->p_ru.ru_nvcsw++;
TD_SET_SLEEPING(td);
mi_switch();
}
/*
* We're awake from voluntary sleep.
*/
CTR3(KTR_PROC, "msleep resume: thread %p (pid %d, %s)", td, p->p_pid,
p->p_comm);
KASSERT(TD_IS_RUNNING(td), ("running but not TDS_RUNNING"));
@ -754,7 +448,7 @@ mi_switch(void)
u_int sched_nest;
mtx_assert(&sched_lock, MA_OWNED | MA_NOTRECURSED);
KASSERT((ke->ke_state == KES_THREAD), ("mi_switch: kse state?"));
KASSERT(!TD_ON_RUNQ(td), ("mi_switch: called by old code"));
#ifdef INVARIANTS
if (!TD_ON_LOCK(td) &&
@ -800,38 +494,21 @@ mi_switch(void)
PCPU_SET(switchtime, new_switchtime);
CTR3(KTR_PROC, "mi_switch: old thread %p (pid %d, %s)", td, p->p_pid,
p->p_comm);
sched_nest = sched_lock.mtx_recurse;
td->td_lastcpu = ke->ke_oncpu;
ke->ke_oncpu = NOCPU;
ke->ke_flags &= ~KEF_NEEDRESCHED;
/*
* At the last moment, if this thread is still marked RUNNING,
* then put it back on the run queue as it has not been suspended
* or stopped or any thing else similar.
*/
if (TD_IS_RUNNING(td)) {
/* Put us back on the run queue (kse and all). */
setrunqueue(td);
} else if (p->p_flag & P_KSES) {
/*
* We will not be on the run queue. So we must be
* sleeping or similar. As it's available,
* someone else can use the KSE if they need it.
* (If bound LOANING can still occur).
*/
kse_reassign(ke);
}
sched_switchout(td);
cpu_switch(); /* SHAZAM!!*/
sched_lock.mtx_recurse = sched_nest;
sched_lock.mtx_lock = (uintptr_t)td;
sched_switchin(td);
/*
* Start setting up stats etc. for the incoming thread.
* Similar code in fork_exit() is returned to by cpu_switch()
* in the case of a new thread/process.
*/
td->td_kse->ke_oncpu = PCPU_GET(cpuid);
sched_lock.mtx_recurse = sched_nest;
sched_lock.mtx_lock = (uintptr_t)td;
CTR3(KTR_PROC, "mi_switch: new thread %p (pid %d, %s)", td, p->p_pid,
p->p_comm);
if (PCPU_GET(switchtime.sec) == 0)
@ -855,7 +532,6 @@ void
setrunnable(struct thread *td)
{
struct proc *p = td->td_proc;
struct ksegrp *kg;
mtx_assert(&sched_lock, MA_OWNED);
switch (p->p_state) {
@ -886,40 +562,8 @@ setrunnable(struct thread *td)
p->p_sflag |= PS_SWAPINREQ;
wakeup(&proc0);
}
} else {
kg = td->td_ksegrp;
if (kg->kg_slptime > 1)
updatepri(kg);
kg->kg_slptime = 0;
setrunqueue(td);
maybe_resched(td);
}
}
/*
* Compute the priority of a process when running in user mode.
* Arrange to reschedule if the resulting priority is better
* than that of the current process.
*/
void
resetpriority(kg)
register struct ksegrp *kg;
{
register unsigned int newpriority;
struct thread *td;
mtx_lock_spin(&sched_lock);
if (kg->kg_pri_class == PRI_TIMESHARE) {
newpriority = PUSER + kg->kg_estcpu / INVERSE_ESTCPU_WEIGHT +
NICE_WEIGHT * (kg->kg_nice - PRIO_MIN);
newpriority = min(max(newpriority, PRI_MIN_TIMESHARE),
PRI_MAX_TIMESHARE);
kg->kg_user_pri = newpriority;
}
FOREACH_THREAD_IN_GROUP(kg, td) {
maybe_resched(td); /* XXXKSE silly */
}
mtx_unlock_spin(&sched_lock);
} else
sched_wakeup(td);
}
/*
@ -973,50 +617,12 @@ static void
sched_setup(dummy)
void *dummy;
{
callout_init(&schedcpu_callout, 1);
callout_init(&roundrobin_callout, 0);
callout_init(&loadav_callout, 0);
/* Kick off timeout driven events by calling first time. */
roundrobin(NULL);
schedcpu(NULL);
loadav(NULL);
}
/*
* We adjust the priority of the current process. The priority of
* a process gets worse as it accumulates CPU time. The cpu usage
* estimator (p_estcpu) is increased here. resetpriority() will
* compute a different priority each time p_estcpu increases by
* INVERSE_ESTCPU_WEIGHT
* (until MAXPRI is reached). The cpu usage estimator ramps up
* quite quickly when the process is running (linearly), and decays
* away exponentially, at a rate which is proportionally slower when
* the system is busy. The basic principle is that the system will
* 90% forget that the process used a lot of CPU time in 5 * loadav
* seconds. This causes the system to favor processes which haven't
* run much recently, and to round-robin among other processes.
*/
void
schedclock(td)
struct thread *td;
{
struct kse *ke;
struct ksegrp *kg;
KASSERT((td != NULL), ("schedclock: null thread pointer"));
ke = td->td_kse;
kg = td->td_ksegrp;
ke->ke_cpticks++;
kg->kg_estcpu = ESTCPULIM(kg->kg_estcpu + 1);
if ((kg->kg_estcpu % INVERSE_ESTCPU_WEIGHT) == 0) {
resetpriority(kg);
if (td->td_priority >= PUSER)
td->td_priority = kg->kg_user_pri;
}
}
/*
* General purpose yield system call
*/
@ -1027,8 +633,8 @@ yield(struct thread *td, struct yield_args *uap)
mtx_assert(&Giant, MA_NOTOWNED);
mtx_lock_spin(&sched_lock);
td->td_priority = PRI_MAX_TIMESHARE;
kg->kg_proc->p_stats->p_ru.ru_nvcsw++;
sched_prio(td, PRI_MAX_TIMESHARE);
mi_switch();
mtx_unlock_spin(&sched_lock);
td->td_retval[0] = 0;

3
sys/kern/ksched.c
View File

@ -41,6 +41,7 @@
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/resource.h>
#include <sys/sched.h>
#include <posix4/posix4.h>
@ -56,7 +57,7 @@ int ksched_attach(struct ksched **p)
struct ksched *ksched= p31b_malloc(sizeof(*ksched));
ksched->rr_interval.tv_sec = 0;
ksched->rr_interval.tv_nsec = 1000000000L / roundrobin_interval();
ksched->rr_interval.tv_nsec = 1000000000L / sched_rr_interval();
*p = ksched;
return 0;

635
sys/kern/sched_4bsd.c Normal file
View File

@ -0,0 +1,635 @@
/*-
* Copyright (c) 1982, 1986, 1990, 1991, 1993
* The Regents of the University of California. All rights reserved.
* (c) UNIX System Laboratories, Inc.
* All or some portions of this file are derived from material licensed
* to the University of California by American Telephone and Telegraph
* Co. or Unix System Laboratories, Inc. and are reproduced herein with
* the permission of UNIX System Laboratories, Inc.
*
* 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.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
*
* $FreeBSD$
*/
#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/resourcevar.h>
#include <sys/sched.h>
#include <sys/smp.h>
#include <sys/sysctl.h>
#include <sys/sx.h>
static int sched_quantum; /* Roundrobin scheduling quantum in ticks. */
#define SCHED_QUANTUM (hz / 10); /* Default sched quantum */
static struct callout schedcpu_callout;
static struct callout roundrobin_callout;
static void roundrobin(void *arg);
static void schedcpu(void *arg);
static void sched_setup(void *dummy);
static void maybe_resched(struct thread *td);
static void updatepri(struct ksegrp *kg);
static void resetpriority(struct ksegrp *kg);
SYSINIT(sched_setup, SI_SUB_KICK_SCHEDULER, SI_ORDER_FIRST, sched_setup, NULL)
/*
* Global run queue.
*/
static struct runq runq;
SYSINIT(runq, SI_SUB_RUN_QUEUE, SI_ORDER_FIRST, runq_init, &runq)
static int
sysctl_kern_quantum(SYSCTL_HANDLER_ARGS)
{
int error, new_val;
new_val = sched_quantum * tick;
error = sysctl_handle_int(oidp, &new_val, 0, req);
if (error != 0 || req->newptr == NULL)
return (error);
if (new_val < tick)
return (EINVAL);
sched_quantum = new_val / tick;
hogticks = 2 * sched_quantum;
return (0);
}
SYSCTL_PROC(_kern, OID_AUTO, quantum, CTLTYPE_INT|CTLFLAG_RW,
0, sizeof sched_quantum, sysctl_kern_quantum, "I",
"Roundrobin scheduling quantum in microseconds");
/*
* Arrange to reschedule if necessary, taking the priorities and
* schedulers into account.
*/
static void
maybe_resched(struct thread *td)
{
mtx_assert(&sched_lock, MA_OWNED);
if (td->td_priority < curthread->td_priority)
curthread->td_kse->ke_flags |= KEF_NEEDRESCHED;
}
/*
* Force switch among equal priority processes every 100ms.
* We don't actually need to force a context switch of the current process.
* The act of firing the event triggers a context switch to softclock() and
* then switching back out again which is equivalent to a preemption, thus
* no further work is needed on the local CPU.
*/
/* ARGSUSED */
static void
roundrobin(void *arg)
{
#ifdef SMP
mtx_lock_spin(&sched_lock);
forward_roundrobin();
mtx_unlock_spin(&sched_lock);
#endif
callout_reset(&roundrobin_callout, sched_quantum, roundrobin, NULL);
}
/*
* Constants for digital decay and forget:
* 90% of (p_estcpu) usage in 5 * loadav time
* 95% of (p_pctcpu) usage in 60 seconds (load insensitive)
* Note that, as ps(1) mentions, this can let percentages
* total over 100% (I've seen 137.9% for 3 processes).
*
* Note that schedclock() updates p_estcpu and p_cpticks asynchronously.
*
* We wish to decay away 90% of p_estcpu in (5 * loadavg) seconds.
* That is, the system wants to compute a value of decay such
* that the following for loop:
* for (i = 0; i < (5 * loadavg); i++)
* p_estcpu *= decay;
* will compute
* p_estcpu *= 0.1;
* for all values of loadavg:
*
* Mathematically this loop can be expressed by saying:
* decay ** (5 * loadavg) ~= .1
*
* The system computes decay as:
* decay = (2 * loadavg) / (2 * loadavg + 1)
*
* We wish to prove that the system's computation of decay
* will always fulfill the equation:
* decay ** (5 * loadavg) ~= .1
*
* If we compute b as:
* b = 2 * loadavg
* then
* decay = b / (b + 1)
*
* We now need to prove two things:
* 1) Given factor ** (5 * loadavg) ~= .1, prove factor == b/(b+1)
* 2) Given b/(b+1) ** power ~= .1, prove power == (5 * loadavg)
*
* Facts:
* For x close to zero, exp(x) =~ 1 + x, since
* exp(x) = 0! + x**1/1! + x**2/2! + ... .
* therefore exp(-1/b) =~ 1 - (1/b) = (b-1)/b.
* For x close to zero, ln(1+x) =~ x, since
* ln(1+x) = x - x**2/2 + x**3/3 - ... -1 < x < 1
* therefore ln(b/(b+1)) = ln(1 - 1/(b+1)) =~ -1/(b+1).
* ln(.1) =~ -2.30
*
* Proof of (1):
* Solve (factor)**(power) =~ .1 given power (5*loadav):
* solving for factor,
* ln(factor) =~ (-2.30/5*loadav), or
* factor =~ exp(-1/((5/2.30)*loadav)) =~ exp(-1/(2*loadav)) =
* exp(-1/b) =~ (b-1)/b =~ b/(b+1). QED
*
* Proof of (2):
* Solve (factor)**(power) =~ .1 given factor == (b/(b+1)):
* solving for power,
* power*ln(b/(b+1)) =~ -2.30, or
* power =~ 2.3 * (b + 1) = 4.6*loadav + 2.3 =~ 5*loadav. QED
*
* Actual power values for the implemented algorithm are as follows:
* loadav: 1 2 3 4
* power: 5.68 10.32 14.94 19.55
*/
/* calculations for digital decay to forget 90% of usage in 5*loadav sec */
#define loadfactor(loadav) (2 * (loadav))
#define decay_cpu(loadfac, cpu) (((loadfac) * (cpu)) / ((loadfac) + FSCALE))
/* decay 95% of `p_pctcpu' in 60 seconds; see CCPU_SHIFT before changing */
static fixpt_t ccpu = 0.95122942450071400909 * FSCALE; /* exp(-1/20) */
SYSCTL_INT(_kern, OID_AUTO, ccpu, CTLFLAG_RD, &ccpu, 0, "");
/* kernel uses `FSCALE', userland (SHOULD) use kern.fscale */
static int fscale __unused = FSCALE;
SYSCTL_INT(_kern, OID_AUTO, fscale, CTLFLAG_RD, 0, FSCALE, "");
/*
* If `ccpu' is not equal to `exp(-1/20)' and you still want to use the
* faster/more-accurate formula, you'll have to estimate CCPU_SHIFT below
* and possibly adjust FSHIFT in "param.h" so that (FSHIFT >= CCPU_SHIFT).
*
* To estimate CCPU_SHIFT for exp(-1/20), the following formula was used:
* 1 - exp(-1/20) ~= 0.0487 ~= 0.0488 == 1 (fixed pt, *11* bits).
*
* If you don't want to bother with the faster/more-accurate formula, you
* can set CCPU_SHIFT to (FSHIFT + 1) which will use a slower/less-accurate
* (more general) method of calculating the %age of CPU used by a process.
*/
#define CCPU_SHIFT 11
/*
* Recompute process priorities, every hz ticks.
* MP-safe, called without the Giant mutex.
*/
/* ARGSUSED */
static void
schedcpu(void *arg)
{
register fixpt_t loadfac = loadfactor(averunnable.ldavg[0]);
struct thread *td;
struct proc *p;
struct kse *ke;
struct ksegrp *kg;
int realstathz;
int awake;
realstathz = stathz ? stathz : hz;
sx_slock(&allproc_lock);
FOREACH_PROC_IN_SYSTEM(p) {
mtx_lock_spin(&sched_lock);
p->p_swtime++;
FOREACH_KSEGRP_IN_PROC(p, kg) {
awake = 0;
FOREACH_KSE_IN_GROUP(kg, ke) {
/*
* Increment time in/out of memory and sleep
* time (if sleeping). We ignore overflow;
* with 16-bit int's (remember them?)
* overflow takes 45 days.
*/
/*
* The kse slptimes are not touched in wakeup
* because the thread may not HAVE a KSE.
*/
if (ke->ke_state == KES_ONRUNQ) {
awake = 1;
ke->ke_flags &= ~KEF_DIDRUN;
} else if ((ke->ke_state == KES_THREAD) &&
(TD_IS_RUNNING(ke->ke_thread))) {
awake = 1;
/* Do not clear KEF_DIDRUN */
} else if (ke->ke_flags & KEF_DIDRUN) {
awake = 1;
ke->ke_flags &= ~KEF_DIDRUN;
}
/*
* pctcpu is only for ps?
* Do it per kse.. and add them up at the end?
* XXXKSE
*/
ke->ke_pctcpu
= (ke->ke_pctcpu * ccpu) >> FSHIFT;
/*
* If the kse has been idle the entire second,
* stop recalculating its priority until
* it wakes up.
*/
if (ke->ke_cpticks == 0)
continue;
#if (FSHIFT >= CCPU_SHIFT)
ke->ke_pctcpu += (realstathz == 100) ?
((fixpt_t) ke->ke_cpticks) <<
(FSHIFT - CCPU_SHIFT) :
100 * (((fixpt_t) ke->ke_cpticks) <<
(FSHIFT - CCPU_SHIFT)) / realstathz;
#else
ke->ke_pctcpu += ((FSCALE - ccpu) *
(ke->ke_cpticks * FSCALE / realstathz)) >>
FSHIFT;
#endif
ke->ke_cpticks = 0;
} /* end of kse loop */
/*
* If there are ANY running threads in this KSEGRP,
* then don't count it as sleeping.
*/
if (awake) {
if (kg->kg_slptime > 1) {
/*
* In an ideal world, this should not
* happen, because whoever woke us
* up from the long sleep should have
* unwound the slptime and reset our
* priority before we run at the stale
* priority. Should KASSERT at some
* point when all the cases are fixed.
*/
updatepri(kg);
}
kg->kg_slptime = 0;
} else {
kg->kg_slptime++;
}
if (kg->kg_slptime > 1)
continue;
kg->kg_estcpu = decay_cpu(loadfac, kg->kg_estcpu);
resetpriority(kg);
FOREACH_THREAD_IN_GROUP(kg, td) {
int changedqueue;
if (td->td_priority >= PUSER) {
/*
* Only change the priority
* of threads that are still at their
* user priority.
* XXXKSE This is problematic
* as we may need to re-order
* the threads on the KSEG list.
*/
changedqueue =
((td->td_priority / RQ_PPQ) !=
(kg->kg_user_pri / RQ_PPQ));
td->td_priority = kg->kg_user_pri;
if (changedqueue && TD_ON_RUNQ(td)) {
/* this could be optimised */
remrunqueue(td);
td->td_priority =
kg->kg_user_pri;
setrunqueue(td);
} else {
td->td_priority = kg->kg_user_pri;
}
}
}
} /* end of ksegrp loop */
mtx_unlock_spin(&sched_lock);
} /* end of process loop */
sx_sunlock(&allproc_lock);
wakeup(&lbolt);
callout_reset(&schedcpu_callout, hz, schedcpu, NULL);
}
/*
* Recalculate the priority of a process after it has slept for a while.
* For all load averages >= 1 and max p_estcpu of 255, sleeping for at
* least six times the loadfactor will decay p_estcpu to zero.
*/
static void
updatepri(struct ksegrp *kg)
{
register unsigned int newcpu;
register fixpt_t loadfac = loadfactor(averunnable.ldavg[0]);
newcpu = kg->kg_estcpu;
if (kg->kg_slptime > 5 * loadfac)
kg->kg_estcpu = 0;
else {
kg->kg_slptime--; /* the first time was done in schedcpu */
while (newcpu && --kg->kg_slptime)
newcpu = decay_cpu(loadfac, newcpu);
kg->kg_estcpu = newcpu;
}
resetpriority(kg);
}
/*
* Compute the priority of a process when running in user mode.
* Arrange to reschedule if the resulting priority is better
* than that of the current process.
*/
static void
resetpriority(struct ksegrp *kg)
{
register unsigned int newpriority;
struct thread *td;
mtx_lock_spin(&sched_lock);
if (kg->kg_pri_class == PRI_TIMESHARE) {
newpriority = PUSER + kg->kg_estcpu / INVERSE_ESTCPU_WEIGHT +
NICE_WEIGHT * (kg->kg_nice - PRIO_MIN);
newpriority = min(max(newpriority, PRI_MIN_TIMESHARE),
PRI_MAX_TIMESHARE);
kg->kg_user_pri = newpriority;
}
FOREACH_THREAD_IN_GROUP(kg, td) {
maybe_resched(td); /* XXXKSE silly */
}
mtx_unlock_spin(&sched_lock);
}
/* ARGSUSED */
static void
sched_setup(void *dummy)
{
if (sched_quantum == 0)
sched_quantum = SCHED_QUANTUM;
hogticks = 2 * sched_quantum;
callout_init(&schedcpu_callout, 1);
callout_init(&roundrobin_callout, 0);
/* Kick off timeout driven events by calling first time. */
roundrobin(NULL);
schedcpu(NULL);
}
/* External interfaces start here */
int
sched_runnable(void)
{
return runq_check(&runq);
}
int
sched_rr_interval(void)
{
if (sched_quantum == 0)
sched_quantum = SCHED_QUANTUM;
return (sched_quantum);
}
/*
* We adjust the priority of the current process. The priority of
* a process gets worse as it accumulates CPU time. The cpu usage
* estimator (p_estcpu) is increased here. resetpriority() will
* compute a different priority each time p_estcpu increases by
* INVERSE_ESTCPU_WEIGHT
* (until MAXPRI is reached). The cpu usage estimator ramps up
* quite quickly when the process is running (linearly), and decays
* away exponentially, at a rate which is proportionally slower when
* the system is busy. The basic principle is that the system will
* 90% forget that the process used a lot of CPU time in 5 * loadav
* seconds. This causes the system to favor processes which haven't
* run much recently, and to round-robin among other processes.
*/
void
sched_clock(struct thread *td)
{
struct kse *ke;
struct ksegrp *kg;
KASSERT((td != NULL), ("schedclock: null thread pointer"));
ke = td->td_kse;
kg = td->td_ksegrp;
ke->ke_cpticks++;
kg->kg_estcpu = ESTCPULIM(kg->kg_estcpu + 1);
if ((kg->kg_estcpu % INVERSE_ESTCPU_WEIGHT) == 0) {
resetpriority(kg);
if (td->td_priority >= PUSER)
td->td_priority = kg->kg_user_pri;
}
}
/*
* charge childs scheduling cpu usage to parent.
*
* XXXKSE assume only one thread & kse & ksegrp keep estcpu in each ksegrp.
* Charge it to the ksegrp that did the wait since process estcpu is sum of
* all ksegrps, this is strictly as expected. Assume that the child process
* aggregated all the estcpu into the 'built-in' ksegrp.
*/
void
sched_exit(struct ksegrp *kg, struct ksegrp *child)
{
kg->kg_estcpu = ESTCPULIM(kg->kg_estcpu + child->kg_estcpu);
}
void
sched_fork(struct ksegrp *kg, struct ksegrp *child)
{
/*
* set priority of child to be that of parent.
* XXXKSE this needs redefining..
*/
child->kg_estcpu = kg->kg_estcpu;
}
void
sched_nice(struct ksegrp *kg, int nice)
{
kg->kg_nice = nice;
resetpriority(kg);
}
void
sched_prio(struct thread *td, u_char prio)
{
td->td_priority = prio;
if (TD_ON_RUNQ(td)) {
remrunqueue(td);
setrunqueue(td);
}
}
void
sched_sleep(struct thread *td, u_char prio)
{
td->td_ksegrp->kg_slptime = 0;
td->td_priority = prio;
}
void
sched_switchin(struct thread *td)
{
td->td_kse->ke_oncpu = PCPU_GET(cpuid);
}
void
sched_switchout(struct thread *td)
{
struct kse *ke;
struct proc *p;
ke = td->td_kse;
p = td->td_proc;
KASSERT((ke->ke_state == KES_THREAD), ("mi_switch: kse state?"));
td->td_lastcpu = ke->ke_oncpu;
ke->ke_oncpu = NOCPU;
ke->ke_flags &= ~KEF_NEEDRESCHED;
/*
* At the last moment, if this thread is still marked RUNNING,
* then put it back on the run queue as it has not been suspended
* or stopped or any thing else similar.
*/
if (TD_IS_RUNNING(td)) {
/* Put us back on the run queue (kse and all). */
setrunqueue(td);
} else if (p->p_flag & P_KSES) {
/*
* We will not be on the run queue. So we must be
* sleeping or similar. As it's available,
* someone else can use the KSE if they need it.
* (If bound LOANING can still occur).
*/
kse_reassign(ke);
}
}
void
sched_wakeup(struct thread *td)
{
struct ksegrp *kg;
kg = td->td_ksegrp;
if (kg->kg_slptime > 1)
updatepri(kg);
kg->kg_slptime = 0;
setrunqueue(td);
maybe_resched(td);
}
void
sched_add(struct kse *ke)
{
mtx_assert(&sched_lock, MA_OWNED);
KASSERT((ke->ke_thread != NULL), ("runq_add: No thread on KSE"));
KASSERT((ke->ke_thread->td_kse != NULL),
("runq_add: No KSE on thread"));
KASSERT(ke->ke_state != KES_ONRUNQ,
("runq_add: kse %p (%s) already in run queue", ke,
ke->ke_proc->p_comm));
KASSERT(ke->ke_proc->p_sflag & PS_INMEM,
("runq_add: process swapped out"));
ke->ke_ksegrp->kg_runq_kses++;
ke->ke_state = KES_ONRUNQ;
runq_add(&runq, ke);
}
void
sched_rem(struct kse *ke)
{
KASSERT(ke->ke_proc->p_sflag & PS_INMEM,
("runq_remove: process swapped out"));
KASSERT((ke->ke_state == KES_ONRUNQ), ("KSE not on run queue"));
mtx_assert(&sched_lock, MA_OWNED);
runq_remove(&runq, ke);
ke->ke_state = KES_THREAD;
ke->ke_ksegrp->kg_runq_kses--;
}
struct kse *
sched_choose(void)
{
struct kse *ke;
ke = runq_choose(&runq);
if (ke != NULL) {
runq_remove(&runq, ke);
ke->ke_state = KES_THREAD;
KASSERT((ke->ke_thread != NULL),
("runq_choose: No thread on KSE"));
KASSERT((ke->ke_thread->td_kse != NULL),
("runq_choose: No KSE on thread"));
KASSERT(ke->ke_proc->p_sflag & PS_INMEM,
("runq_choose: process swapped out"));
}
return (ke);
}
void
sched_userret(struct thread *td)
{
struct ksegrp *kg;
/*
* 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.
*/
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);
}
}

18
sys/kern/subr_trap.c
View File

@ -53,6 +53,7 @@
#include <sys/kse.h>
#include <sys/ktr.h>
#include <sys/resourcevar.h>
#include <sys/sched.h>
#include <sys/signalvar.h>
#include <sys/systm.h>
#include <sys/vmmeter.h>
@ -73,7 +74,6 @@ userret(td, frame, oticks)
{
struct proc *p = td->td_proc;
struct kse *ke = td->td_kse;
struct ksegrp *kg = td->td_ksegrp;
CTR3(KTR_SYSC, "userret: thread %p (pid %d, %s)", td, p->p_pid,
p->p_comm);
@ -95,19 +95,9 @@ userret(td, frame, oticks)
#endif
/*
* 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.
* Let the scheduler adjust our priority etc.
*/
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);
}
sched_userret(td);
/*
* We need to check to see if we have to exit or wait due to a
@ -250,7 +240,7 @@ ast(struct trapframe *framep)
}
if (flags & KEF_NEEDRESCHED) {
mtx_lock_spin(&sched_lock);
td->td_priority = kg->kg_user_pri;
sched_prio(td, kg->kg_user_pri);
p->p_stats->p_ru.ru_nivcsw++;
mi_switch();
mtx_unlock_spin(&sched_lock);

6
sys/kern/subr_turnstile.c
View File

@ -47,6 +47,7 @@
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/resourcevar.h>
#include <sys/sched.h>
#include <sys/sbuf.h>
#include <sys/stdint.h>
#include <sys/sysctl.h>
@ -146,13 +147,10 @@ propagate_priority(struct thread *td)
* If on run queue move to new run queue, and quit.
* XXXKSE this gets a lot more complicated under threads
* but try anyhow.
* We should have a special call to do this more efficiently.
*/
if (TD_ON_RUNQ(td)) {
MPASS(td->td_blocked == NULL);
remrunqueue(td);
td->td_priority = pri;
setrunqueue(td);
sched_prio(td, pri);
return;
}
/*

3
sys/posix4/ksched.c
View File

@ -41,6 +41,7 @@
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/resource.h>
#include <sys/sched.h>
#include <posix4/posix4.h>
@ -56,7 +57,7 @@ int ksched_attach(struct ksched **p)
struct ksched *ksched= p31b_malloc(sizeof(*ksched));
ksched->rr_interval.tv_sec = 0;
ksched->rr_interval.tv_nsec = 1000000000L / roundrobin_interval();
ksched->rr_interval.tv_nsec = 1000000000L / sched_rr_interval();
*p = ksched;
return 0;

6
sys/sys/proc.h
View File

@ -872,9 +872,6 @@ void proc_linkup(struct proc *p, struct ksegrp *kg,
struct kse *ke, struct thread *td);
void proc_reparent(struct proc *child, struct proc *newparent);
void remrunqueue(struct thread *);
void resetpriority(struct ksegrp *);
int roundrobin_interval(void);
void schedclock(struct thread *);
int securelevel_ge(struct ucred *cr, int level);
int securelevel_gt(struct ucred *cr, int level);
void setrunnable(struct thread *);
@ -886,9 +883,7 @@ void cpu_idle(void);
void cpu_switch(void);
void cpu_throw(void) __dead2;
void unsleep(struct thread *);
void updatepri(struct ksegrp *);
void userret(struct thread *, struct trapframe *, u_int);
void maybe_resched(struct thread *);
void cpu_exit(struct thread *);
void cpu_sched_exit(struct thread *);
@ -911,7 +906,6 @@ void cpu_thread_setup(struct thread *td);
void kse_reassign(struct kse *ke);
void kse_link(struct kse *ke, struct ksegrp *kg);
void ksegrp_link(struct ksegrp *kg, struct proc *p);
int kserunnable(void);
void make_kse_runnable(struct kse *ke);
struct thread *signal_upcall(struct proc *p, int sig);
void thread_exit(void) __dead2;

65
sys/sys/sched.h Normal file
View File

@ -0,0 +1,65 @@
/*-
* Copyright (c) 2002, 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.
*
* $FreeBSD$
*/
#ifndef _SYS_SCHED_H_
#define _SYS_SCHED_H_
/*
* General scheduling info.
*/
int sched_rr_interval(void);
int sched_runnable(void);
/*
* KSE Groups contain scheduling priority information. They record the
* behavior of groups of KSEs and threads.
*/
void sched_exit(struct ksegrp *kg, struct ksegrp *child);
void sched_fork(struct ksegrp *kg, struct ksegrp *child);
void sched_nice(struct ksegrp *kg, int nice);
void sched_prio(struct thread *td, u_char prio);
void sched_userret(struct thread *td);
/*
* Threads are switched in and out, block on resources, and have temporary
* priorities inherited from their ksegs.
*/
void sched_clock(struct thread *td);
void sched_sleep(struct thread *td, u_char prio);
void sched_switchin(struct thread *td);
void sched_switchout(struct thread *td);
void sched_wakeup(struct thread *td);
/*
* KSEs are moved on and off of run queues.
*/
void sched_add(struct kse *ke);
void sched_rem(struct kse *ke);
struct kse *sched_choose(void);
#endif /* !_SYS_SCHED_H_ */

5
sys/vm/vm_pageout.c
View File

@ -82,6 +82,7 @@
#include <sys/kthread.h>
#include <sys/ktr.h>
#include <sys/resourcevar.h>
#include <sys/sched.h>
#include <sys/signalvar.h>
#include <sys/vnode.h>
#include <sys/vmmeter.h>
@ -1191,9 +1192,7 @@ vm_pageout_scan(int pass)
killproc(bigproc, "out of swap space");
mtx_lock_spin(&sched_lock);
FOREACH_KSEGRP_IN_PROC(bigproc, kg) {
kg->kg_estcpu = 0;
kg->kg_nice = PRIO_MIN; /* XXXKSE ??? */
resetpriority(kg);
sched_nice(kg, PRIO_MIN); /* XXXKSE ??? */
}
mtx_unlock_spin(&sched_lock);
PROC_UNLOCK(bigproc);

3
sys/vm/vm_zeroidle.c
View File

@ -18,6 +18,7 @@
#include <sys/vmmeter.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/sched.h>
#include <sys/sysctl.h>
#include <sys/kthread.h>
@ -128,7 +129,7 @@ vm_pagezero(void)
for (;;) {
if (vm_page_zero_check()) {
pages += vm_page_zero_idle();
if (pages > idlezero_maxrun || kserunnable()) {
if (pages > idlezero_maxrun || sched_runnable()) {
mtx_lock_spin(&sched_lock);
td->td_proc->p_stats->p_ru.ru_nvcsw++;
mi_switch();