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Turned off the "calcru: negative time" warning for certain SMP cases

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where it is known to detect a problem but the problem is not very easy
to fix.  The warning became very common recently after a call to calcru()
was added to fill_kinfo_thread().

Another (much older) cause of "negative times" (actually non-monotonic
times) was fixed in rev.1.237 of kern_exit.c.

Print separate messages for non-monotonic and negative times.
This commit is contained in:
bde 2004-06-21 17:46:27 +00:00
parent 2897581d0a
commit 459a8e3950
1 changed files with 34 additions and 12 deletions
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46
sys/kern/kern_resource.c
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@ -701,10 +701,12 @@ calcru(p, up, sp, ip)
struct timeval *sp;
struct timeval *ip;
{
struct bintime bt;
struct bintime bt, rt;
struct timeval tv;
struct thread *td;
/* {user, system, interrupt, total} {ticks, usec}; previous tu: */
u_int64_t ut, uu, st, su, it, iu, tt, tu, ptu;
int problemcase;
mtx_assert(&sched_lock, MA_OWNED);
/* XXX: why spl-protect ? worst case is an off-by-one report */
@ -718,24 +720,44 @@ calcru(p, up, sp, ip)
st = 1;
tt = 1;
}
if (p == curthread->td_proc) {
rt = p->p_runtime;
problemcase = 0;
FOREACH_THREAD_IN_PROC(p, td) {
/*
* 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.
* XXXKSE use a different test due to threads on other
* processors also being 'current'.
*/
binuptime(&bt);
bintime_sub(&bt, PCPU_PTR(switchtime));
bintime_add(&bt, &p->p_runtime);
} else
bt = p->p_runtime;
bintime2timeval(&bt, &tv);
if (td == curthread) {
binuptime(&bt);
bintime_sub(&bt, PCPU_PTR(switchtime));
bintime_add(&rt, &bt);
} else if (TD_IS_RUNNING(td)) {
/*
* XXX: this case should add the difference between
* the current time and the switch time as above,
* but the switch time is inaccessible, so we can't
* do the adjustment and will end up with a wrong
* runtime. A previous call with a different
* curthread may have obtained a (right or wrong)
* runtime that is in advance of ours. Just set a
* flag to avoid warning about this known problem.
*/
problemcase = 1;
}
}
bintime2timeval(&rt, &tv);
tu = (u_int64_t)tv.tv_sec * 1000000 + tv.tv_usec;
ptu = p->p_uu + p->p_su + p->p_iu;
if (tu < ptu || (int64_t)tu < 0) {
printf("calcru: negative time of %jd usec for pid %d (%s)\n",
if (tu < ptu) {
if (!problemcase)
printf(
"calcru: runtime went backwards from %ju usec to %ju usec for pid %d (%s)\n",
(uintmax_t)ptu, (uintmax_t)tu, p->p_pid, p->p_comm);
tu = ptu;
}
if ((int64_t)tu < 0) {
printf("calcru: negative runtime of %jd usec for pid %d (%s)\n",
(intmax_t)tu, p->p_pid, p->p_comm);
tu = ptu;
}