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Protect update of the per processor switchtime variable against

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interrupts.

Protect usage of the per processor switchtime variable against
interrupts in calcru().

This seem to eliminate the "microuptime() went backwards" warnings.
This commit is contained in:
Tor Egge 2001-02-22 19:50:37 +00:00
parent e6c77250ef
commit 0d139b3741
2 changed files with 19 additions and 7 deletions
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6
sys/kern/kern_exit.c
View File

@ -118,6 +118,7 @@ exit1(p, rv)
register struct proc *q, *nq;
register struct vmspace *vm;
struct exitlist *ep;
struct timeval new_switchtime;
if (p->p_pid == 1) {
printf("init died (signal %d, exit %d)\n",
@ -325,7 +326,10 @@ exit1(p, rv)
* directly. Set it now so that the rest of the exit time gets
* counted somewhere if possible.
*/
microuptime(PCPU_PTR(switchtime));
mtx_lock_spin(&sched_lock);
microuptime(&new_switchtime);
PCPU_SET(switchtime, new_switchtime);
mtx_unlock_spin(&sched_lock);
PCPU_SET(switchticks, ticks);
/*

20
sys/kern/kern_resource.c
View File

@ -567,19 +567,27 @@ calcru(p, up, sp, ip)
tu = p->p_runtime;
if (p == curproc) {
struct timeval old_switchtime;
/*
* Adjust for the current time slice. This is actually fairly
* important since the error here is on the order of a time
* quantum, which is much greater than the sampling error.
*/
microuptime(&tv);
if (timevalcmp(&tv, PCPU_PTR(switchtime), <))
do {
old_switchtime = PCPU_GET(switchtime);
microuptime(&tv);
} while (old_switchtime.tv_sec !=
PCPU_GET(switchtime.tv_sec) ||
old_switchtime.tv_usec !=
PCPU_GET(switchtime.tv_usec));
if (timevalcmp(&tv, &old_switchtime, <))
printf("microuptime() went backwards (%ld.%06ld -> %ld.%06ld)\n",
PCPU_GET(switchtime.tv_sec), PCPU_GET(switchtime.tv_usec),
tv.tv_sec, tv.tv_usec);
old_switchtime.tv_sec,
old_switchtime.tv_usec,
tv.tv_sec, tv.tv_usec);
else
tu += (tv.tv_usec - PCPU_GET(switchtime.tv_usec)) +
(tv.tv_sec - PCPU_GET(switchtime.tv_sec)) *
tu += (tv.tv_usec - old_switchtime.tv_usec) +
(tv.tv_sec - old_switchtime.tv_sec) *
(int64_t)1000000;
}
ptu = p->p_uu + p->p_su + p->p_iu;