perf: PERF_EVENT_IOC_RESET and multiplexing
From: Vince Weaver
Date: Mon Aug 20 2012 - 14:53:52 EST
Hello
I have a perf API question.
When I run PERF_EVENT_IOC_RESET, all it resets is the event count.
It does not reset the PERF_FORMAT_TOTAL_TIME_ENABLED or
PERF_FORMAT_TOTAL_TIME_RUNNING values.
Is this expected? It means if I'm trying to do multiplexing and want to
reset the counts to zero, there's no way to reset the enabled/running
values.
I suppose I can just close/reopen the events, or allocate some space to
store the previous values, but that seems like unncessary overhead.
As an aside while I have your attention, can someone explain the
difference between the "inherit" and the "inherit_stat" options in
perf.attr? I can't seem to make a test case exhibit a difference, and
the events/core.c code in the kernel is a horrible wall of uncommented
code that is nearly impossible to follow.
Thanks,
Vince
vweaver1@xxxxxxxxxxxx
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