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author | Steven Rostedt <srostedt@redhat.com> | 2009-03-24 01:10:15 -0400 |
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committer | Steven Rostedt <srostedt@redhat.com> | 2009-03-24 09:33:30 -0400 |
commit | 8aef2d2856158a36c295a8d1288281e4839bff13 (patch) | |
tree | eef85397dedcad001982724e0be2da6dc089b39f /include | |
parent | 05ce5818adee8f8efd0a5ca0d900a6789012516b (diff) | |
download | linux-8aef2d2856158a36c295a8d1288281e4839bff13.tar.gz linux-8aef2d2856158a36c295a8d1288281e4839bff13.tar.bz2 linux-8aef2d2856158a36c295a8d1288281e4839bff13.zip |
function-graph: ignore times across schedule
Impact: more accurate timings
The current method of function graph tracing does not take into
account the time spent when a task is not running. This shows functions
that call schedule have increased costs:
3) + 18.664 us | }
------------------------------------------
3) <idle>-0 => kblockd-123
------------------------------------------
3) | finish_task_switch() {
3) 1.441 us | _spin_unlock_irq();
3) 3.966 us | }
3) ! 2959.433 us | }
3) ! 2961.465 us | }
This patch uses the tracepoint in the scheduling context switch to
account for time that has elapsed while a task is scheduled out.
Now we see:
------------------------------------------
3) <idle>-0 => edac-po-1067
------------------------------------------
3) | finish_task_switch() {
3) 0.685 us | _spin_unlock_irq();
3) 2.331 us | }
3) + 41.439 us | }
3) + 42.663 us | }
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Diffstat (limited to 'include')
-rw-r--r-- | include/linux/sched.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h index 89cd308cc7a5..471e36d30123 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1409,6 +1409,8 @@ struct task_struct { int curr_ret_stack; /* Stack of return addresses for return function tracing */ struct ftrace_ret_stack *ret_stack; + /* time stamp for last schedule */ + unsigned long long ftrace_timestamp; /* * Number of functions that haven't been traced * because of depth overrun. |