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Add instrumentation which tells us how much work softclock() does

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per invocation.
This commit is contained in:
Poul-Henning Kamp 2003-06-04 05:25:58 +00:00
parent 8c401bb94d
commit 22ee8c4f50
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=115810
1 changed files with 25 additions and 1 deletions
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26
sys/kern/kern_timeout.c
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@ -45,7 +45,17 @@
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/sysctl.h>
static int avg_depth;
SYSCTL_INT(_debug, OID_AUTO, to_avg_depth, CTLFLAG_RD, &avg_depth, 0,
"Average number of items examined per softclock call. Units = 1/1000");
static int avg_gcalls;
SYSCTL_INT(_debug, OID_AUTO, to_avg_gcalls, CTLFLAG_RD, &avg_gcalls, 0,
"Average number of Giant callouts made per softclock call. Units = 1/1000");
static int avg_mpcalls;
SYSCTL_INT(_debug, OID_AUTO, to_avg_mpcalls, CTLFLAG_RD, &avg_mpcalls, 0,
"Average number of MP callouts made per softclock call. Units = 1/1000");
/*
* TODO:
* allocate more timeout table slots when table overflows.
@ -133,6 +143,9 @@ softclock(void *dummy)
struct callout_tailq *bucket;
int curticks;
int steps; /* #steps since we last allowed interrupts */
int depth;
int mpcalls;
int gcalls;
#ifdef DIAGNOSTIC
struct bintime bt1, bt2;
struct timespec ts2;
@ -143,6 +156,9 @@ softclock(void *dummy)
#define MAX_SOFTCLOCK_STEPS 100 /* Maximum allowed value of steps. */
#endif /* MAX_SOFTCLOCK_STEPS */
mpcalls = 0;
gcalls = 0;
depth = 0;
steps = 0;
mtx_lock_spin(&callout_lock);
while (softticks != ticks) {
@ -155,6 +171,7 @@ softclock(void *dummy)
bucket = &callwheel[curticks & callwheelmask];
c = TAILQ_FIRST(bucket);
while (c) {
depth++;
if (c->c_time != curticks) {
c = TAILQ_NEXT(c, c_links.tqe);
++steps;
@ -187,8 +204,12 @@ softclock(void *dummy)
(c->c_flags & ~CALLOUT_PENDING);
}
mtx_unlock_spin(&callout_lock);
if (!(c_flags & CALLOUT_MPSAFE))
if (!(c_flags & CALLOUT_MPSAFE)) {
mtx_lock(&Giant);
gcalls++;
} else {
mpcalls++;
}
#ifdef DIAGNOSTIC
binuptime(&bt1);
#endif
@ -213,6 +234,9 @@ softclock(void *dummy)
}
}
}
avg_depth += (depth * 1000 - avg_depth) >> 8;
avg_mpcalls += (mpcalls * 1000 - avg_mpcalls) >> 8;
avg_gcalls += (gcalls * 1000 - avg_gcalls) >> 8;
nextsoftcheck = NULL;
mtx_unlock_spin(&callout_lock);
}