svn commit: r187664 - head/sys/kern
Robert Watson
rwatson at FreeBSD.org
Sat Jan 24 02:22:51 PST 2009
Author: rwatson
Date: Sat Jan 24 10:22:49 2009
New Revision: 187664
URL: http://svn.freebsd.org/changeset/base/187664
Log:
Add explicit static DTrace tracing to the callout mechanism, capturing
pointers to the callout handler just before and just after the callout
it invoked. I attempted to do this in a manner congruent to tracing in
Solaris's callout mechanism, but couldn't quite use the same names due
to convention and syntax differences.
Example DTrace script to generate a distribution graph of callout
execution times:
callout_execute:::callout_start
{
self->cstart = timestamp;
}
callout_execute:::callout_end
{
@length = quantize(timestamp - self->cstart);
}
Reviewed by: jb
MFC after: 3 days
Modified:
head/sys/kern/kern_timeout.c
Modified: head/sys/kern/kern_timeout.c
==============================================================================
--- head/sys/kern/kern_timeout.c Sat Jan 24 05:32:11 2009 (r187663)
+++ head/sys/kern/kern_timeout.c Sat Jan 24 10:22:49 2009 (r187664)
@@ -37,6 +37,8 @@
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
+#include "opt_kdtrace.h"
+
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bus.h>
@@ -49,10 +51,19 @@ __FBSDID("$FreeBSD$");
#include <sys/malloc.h>
#include <sys/mutex.h>
#include <sys/proc.h>
+#include <sys/sdt.h>
#include <sys/sleepqueue.h>
#include <sys/sysctl.h>
#include <sys/smp.h>
+SDT_PROVIDER_DEFINE(callout_execute);
+SDT_PROBE_DEFINE(callout_execute, kernel, , callout_start);
+SDT_PROBE_ARGTYPE(callout_execute, kernel, , callout_start, 0,
+ "struct callout *");
+SDT_PROBE_DEFINE(callout_execute, kernel, , callout_end);
+SDT_PROBE_ARGTYPE(callout_execute, kernel, , callout_end, 0,
+ "struct callout *");
+
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");
@@ -395,7 +406,11 @@ softclock(void *arg)
binuptime(&bt1);
#endif
THREAD_NO_SLEEPING();
+ SDT_PROBE(callout_execute, kernel, ,
+ callout_start, c, 0, 0, 0, 0);
c_func(c_arg);
+ SDT_PROBE(callout_execute, kernel, ,
+ callout_end, c, 0, 0, 0, 0);
THREAD_SLEEPING_OK();
#ifdef DIAGNOSTIC
binuptime(&bt2);
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