[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>
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 8fe6b83..2a40d9f 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1294,6 +1294,7 @@
Param: "schedule" - profile schedule points.
Param: <number> - step/bucket size as a power of 2 for
statistical time based profiling.
+ Param: "sleep" - profile D-state sleeping (millisecs)
processor.max_cstate= [HW,ACPI]
Limit processor to maximum C-state
