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authorIngo Molnar <mingo@elte.hu>2006-12-06 20:37:24 -0800
committerLinus Torvalds <torvalds@woody.osdl.org>2006-12-07 08:39:36 -0800
commitece8a684c75df215320b4155944979e3f78c5c93 (patch)
tree2a65e786dd70ab368c12836a39c36070c0e4974f /kernel/sched.c
parent70888bd5b70579e278d5ef1b7e1ec6a420d38b9e (diff)
[PATCH] sleep profiling
Implement prof=sleep profiling. TASK_UNINTERRUPTIBLE sleeps will be taken as a profile hit, and every millisecond spent sleeping causes a profile-hit for the call site that initiated the sleep. Sample readprofile output on i386: 306 ps2_sendbyte 1.3973 432 call_usermodehelper_keys 1.9548 484 ps2_command 0.6453 790 __driver_attach 4.7879 1593 msleep 44.2500 3976 sync_buffer 64.1290 4076 do_lookup 12.4648 8587 sync_page 122.6714 20820 total 0.0067 (NOTE: architectures need to check whether get_wchan() can be called from deep within the wakeup path.) akpm: we need to mark more functions __sched. lock_sock(), msleep(), others.. akpm: the contention in do_lookup() is a surprise. Presumably doing disk reads for directory contents while holding i_mutex. [akpm@osdl.org: various fixes] Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'kernel/sched.c')
-rw-r--r--kernel/sched.c11
1 files changed, 11 insertions, 0 deletions
diff --git a/kernel/sched.c b/kernel/sched.c
index 343e1794233e..75a005ed4eda 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -948,6 +948,17 @@ static void activate_task(struct task_struct *p, struct rq *rq, int local)
}
#endif
+ /*
+ * Sleep time is in units of nanosecs, so shift by 20 to get a
+ * milliseconds-range estimation of the amount of time that the task
+ * spent sleeping:
+ */
+ if (unlikely(prof_on == SLEEP_PROFILING)) {
+ if (p->state == TASK_UNINTERRUPTIBLE)
+ profile_hits(SLEEP_PROFILING, (void *)get_wchan(p),
+ (now - p->timestamp) >> 20);
+ }
+
if (!rt_task(p))
p->prio = recalc_task_prio(p, now);