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Add some code to allow threads to nominat a sibling to run if theyu are going to sleep.

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MFC after:	1 week
This commit is contained in:
Julian Elischer 2004-09-10 21:04:38 +00:00
parent 3071824ff0
commit 3389af30e8
5 changed files with 55 additions and 9 deletions
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10
sys/kern/kern_switch.c
View File

@ -192,7 +192,7 @@ retry:
* sched_thread_exit() (local)
* sched_switch() (local)
* sched_thread_exit() (local)
* remrunqueue() (local) (commented out)
* remrunqueue() (local)
*/
static void
slot_fill(struct ksegrp *kg)
@ -224,7 +224,7 @@ slot_fill(struct ksegrp *kg)
}
}
#if 0
#ifdef SCHED_4BSD
/*
* Remove a thread from its KSEGRP's run queue.
* This in turn may remove it from a KSE if it was already assigned
@ -248,7 +248,7 @@ remrunqueue(struct thread *td)
* If it is not a threaded process, take the shortcut.
*/
if ((td->td_proc->p_flag & P_HADTHREADS) == 0) {
/* Bring its kse with it, leave the thread attached */
/* remve from sys run queue and free up a slot */
sched_rem(td);
kg->kg_avail_opennings++;
ke->ke_state = KES_THREAD;
@ -259,7 +259,7 @@ remrunqueue(struct thread *td)
kg->kg_runnable--;
if (ke->ke_state == KES_ONRUNQ) {
/*
* This thread has been assigned to a KSE.
* This thread has been assigned to the system run queue.
* We need to dissociate it and try assign the
* KSE to the next available thread. Then, we should
* see if we need to move the KSE in the run queues.
@ -271,7 +271,7 @@ remrunqueue(struct thread *td)
KASSERT((td2 != NULL), ("last assigned has wrong value"));
if (td2 == td)
kg->kg_last_assigned = td3;
slot_fill(kg);
/* slot_fill(kg); */ /* will replace it with another */
}
}
#endif

2
sys/kern/kern_synch.c
View File

@ -337,7 +337,7 @@ mi_switch(int flags, struct thread *newtd)
(void *)td, td->td_sched, (long)p->p_pid, p->p_comm);
if (td->td_proc->p_flag & P_SA)
newtd = thread_switchout(td, flags, newtd);
sched_switch(td, newtd);
sched_switch(td, newtd, flags);
CTR4(KTR_PROC, "mi_switch: new thread %p (kse %p, pid %ld, %s)",
(void *)td, td->td_sched, (long)p->p_pid, p->p_comm);

48
sys/kern/sched_4bsd.c
View File

@ -247,7 +247,22 @@ static int forward_wakeup_use_htt = 0;
SYSCTL_INT(_kern_sched_ipiwakeup, OID_AUTO, htt2, CTLFLAG_RW,
&forward_wakeup_use_htt, 0,
"account for htt");
#endif
static int sched_followon = 0;
SYSCTL_INT(_kern_sched, OID_AUTO, followon, CTLFLAG_RW,
&sched_followon, 0,
"allow threads to share a quantum");
static int sched_pfollowons = 0;
SYSCTL_INT(_kern_sched, OID_AUTO, pfollowons, CTLFLAG_RD,
&sched_pfollowons, 0,
"number of followons done to a different ksegrp");
static int sched_kgfollowons = 0;
SYSCTL_INT(_kern_sched, OID_AUTO, kgfollowons, CTLFLAG_RD,
&sched_kgfollowons, 0,
"number of followons done in a ksegrp");
/*
* Arrange to reschedule if necessary, taking the priorities and
@ -733,10 +748,13 @@ sched_sleep(struct thread *td)
td->td_base_pri = td->td_priority;
}
static void remrunqueue(struct thread *td);
void
sched_switch(struct thread *td, struct thread *newtd)
sched_switch(struct thread *td, struct thread *newtd, int flags)
{
struct kse *ke;
struct ksegrp *kg;
struct proc *p;
ke = td->td_kse;
@ -746,6 +764,33 @@ sched_switch(struct thread *td, struct thread *newtd)
if ((p->p_flag & P_NOLOAD) == 0)
sched_tdcnt--;
/*
* We are volunteering to switch out so we get to nominate
* a successor for the rest of our quantum
* First try another thread in our ksegrp, and then look for
* other ksegrps in our process.
*/
if (sched_followon &&
(p->p_flag & P_HADTHREADS) &&
(flags & SW_VOL) &&
newtd == NULL) {
/* lets schedule another thread from this process */
kg = td->td_ksegrp;
if ((newtd = TAILQ_FIRST(&kg->kg_runq))) {
remrunqueue(newtd);
sched_kgfollowons++;
} else {
FOREACH_KSEGRP_IN_PROC(p, kg) {
if ((newtd = TAILQ_FIRST(&kg->kg_runq))) {
sched_pfollowons++;
remrunqueue(newtd);
break;
}
}
}
}
/*
* The thread we are about to run needs to be counted as if it had been
* added to the run queue and selected.
@ -757,6 +802,7 @@ sched_switch(struct thread *td, struct thread *newtd)
if ((newtd->td_proc->p_flag & P_NOLOAD) == 0)
sched_tdcnt++;
}
td->td_lastcpu = td->td_oncpu;
td->td_flags &= ~TDF_NEEDRESCHED;
td->td_pflags &= ~TDP_OWEPREEMPT;

2
sys/kern/sched_ule.c
View File

@ -1225,7 +1225,7 @@ sched_prio(struct thread *td, u_char prio)
}
void
sched_switch(struct thread *td, struct thread *newtd)
sched_switch(struct thread *td, struct thread *newtd, int flags)
{
struct kse *ke;

2
sys/sys/sched.h
View File

@ -66,7 +66,7 @@ void sched_fork_thread(struct thread *td, struct thread *child);
fixpt_t sched_pctcpu(struct thread *td);
void sched_prio(struct thread *td, u_char prio);
void sched_sleep(struct thread *td);
void sched_switch(struct thread *td, struct thread *newtd);
void sched_switch(struct thread *td, struct thread *newtd, int flags);
void sched_userret(struct thread *td);
void sched_wakeup(struct thread *td);