Author: jhb
Date: Tue Jan 3 21:03:28 2012
New Revision: 229429
URL: http://svn.freebsd.org/changeset/base/229429
Log:
Some small fixes to CPU accounting for threads:
- Only initialize the per-cpu switchticks and switchtime in sched_throw()
for the very first context switch on APs during boot. This avoids a
small gap between the middle of thread_exit() and sched_throw() where
time is not accounted to any thread.
- In thread_exit(), update the timestamp bookkeeping to track the changes
to mi_switch() introduced by td_rux so that the code once again matches
the comment claiming it is mimicing mi_switch(). Specifically, only
update the per-thread stats directly and depend on ruxagg() to update
p_rux rather than adjusting p_rux directly. While here, move the
timestamp bookkeeping as late in the function as possible.
Reviewed by: bde, kib
MFC after: 1 week
Modified:
head/sys/kern/kern_thread.c
head/sys/kern/sched_4bsd.c
head/sys/kern/sched_ule.c
Modified: head/sys/kern/kern_thread.c
==============================================================================
--- head/sys/kern/kern_thread.c Tue Jan 3 21:03:20 2012 (r229428)
+++ head/sys/kern/kern_thread.c Tue Jan 3 21:03:28 2012 (r229429)
@@ -381,7 +381,7 @@ thread_free(struct thread *td)
void
thread_exit(void)
{
- uint64_t new_switchtime;
+ uint64_t runtime, new_switchtime;
struct thread *td;
struct thread *td2;
struct proc *p;
@@ -410,15 +410,6 @@ thread_exit(void)
*/
cpu_thread_exit(td); /* XXXSMP */
- /* Do the same timestamp bookkeeping that mi_switch() would do. */
- new_switchtime = cpu_ticks();
- p->p_rux.rux_runtime += (new_switchtime - PCPU_GET(switchtime));
- PCPU_SET(switchtime, new_switchtime);
- PCPU_SET(switchticks, ticks);
- PCPU_INC(cnt.v_swtch);
- /* Save our resource usage in our process. */
- td->td_ru.ru_nvcsw++;
- rucollect(&p->p_ru, &td->td_ru);
/*
* The last thread is left attached to the process
* So that the whole bundle gets recycled. Skip
@@ -467,7 +458,21 @@ thread_exit(void)
PMC_SWITCH_CONTEXT(td, PMC_FN_CSW_OUT);
#endif
PROC_UNLOCK(p);
+
+ /* Do the same timestamp bookkeeping that mi_switch() would do. */
+ new_switchtime = cpu_ticks();
+ runtime = new_switchtime - PCPU_GET(switchtime);
+ td->td_runtime += runtime;
+ td->td_incruntime += runtime;
+ PCPU_SET(switchtime, new_switchtime);
+ PCPU_SET(switchticks, ticks);
+ PCPU_INC(cnt.v_swtch);
+
+ /* Save our resource usage in our process. */
+ td->td_ru.ru_nvcsw++;
ruxagg(p, td);
+ rucollect(&p->p_ru, &td->td_ru);
+
thread_lock(td);
PROC_SUNLOCK(p);
td->td_state = TDS_INACTIVE;
Modified: head/sys/kern/sched_4bsd.c
==============================================================================
--- head/sys/kern/sched_4bsd.c Tue Jan 3 21:03:20 2012 (r229428)
+++ head/sys/kern/sched_4bsd.c Tue Jan 3 21:03:28 2012 (r229429)
@@ -1572,14 +1572,14 @@ sched_throw(struct thread *td)
if (td == NULL) {
mtx_lock_spin(&sched_lock);
spinlock_exit();
+ PCPU_SET(switchtime, cpu_ticks());
+ PCPU_SET(switchticks, ticks);
} else {
lock_profile_release_lock(&sched_lock.lock_object);
MPASS(td->td_lock == &sched_lock);
}
mtx_assert(&sched_lock, MA_OWNED);
KASSERT(curthread->td_md.md_spinlock_count == 1, ("invalid count"));
- PCPU_SET(switchtime, cpu_ticks());
- PCPU_SET(switchticks, ticks);
cpu_throw(td, choosethread()); /* doesn't return */
}
Modified: head/sys/kern/sched_ule.c
==============================================================================
--- head/sys/kern/sched_ule.c Tue Jan 3 21:03:20 2012 (r229428)
+++ head/sys/kern/sched_ule.c Tue Jan 3 21:03:28 2012 (r229429)
@@ -2587,6 +2587,8 @@ sched_throw(struct thread *td)
/* Correct spinlock nesting and acquire the correct lock. */
TDQ_LOCK(tdq);
spinlock_exit();
+ PCPU_SET(switchtime, cpu_ticks());
+ PCPU_SET(switchticks, ticks);
} else {
MPASS(td->td_lock == TDQ_LOCKPTR(tdq));
tdq_load_rem(tdq, td);
@@ -2595,8 +2597,6 @@ sched_throw(struct thread *td)
KASSERT(curthread->td_md.md_spinlock_count == 1, ("invalid count"));
newtd = choosethread();
TDQ_LOCKPTR(tdq)->mtx_lock = (uintptr_t)newtd;
- PCPU_SET(switchtime, cpu_ticks());
- PCPU_SET(switchticks, ticks);
cpu_throw(td, newtd); /* doesn't return */
}
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