path: root/Documentation
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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 /Documentation
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 'Documentation')
1 files changed, 1 insertions, 0 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 8fe6b834ef27..2a40d9f6ffad 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1294,6 +1294,7 @@ and is between 256 and 4096 characters. It is defined in the file
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