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| author |   Peter Zijlstra <peterz@infradead.org> | 2017-08-03 15:42:09 +0200 |
|---|---|---|
| committer |   Ingo Molnar <mingo@kernel.org> | 2017-08-10 12:01:09 +0200 |
| commit | 9b231d9f47c6114d317ce28cff92a74ad80547f5 (patch) | |
| tree | 97e34b1a82a56ab28046055a0c4dfc6d288c228f /arch | |
| parent | perf/x86: Fix RDPMC vs. mm_struct tracking (diff) | |
| download | linux-dev-9b231d9f47c6114d317ce28cff92a74ad80547f5.tar.xz linux-dev-9b231d9f47c6114d317ce28cff92a74ad80547f5.zip | |
perf/core: Fix time on IOC_ENABLE
Vince reported that when we do IOC_ENABLE/IOC_DISABLE while the task
is SIGSTOP'ed state the timestamps go wobbly.
It turns out we indeed fail to correctly account time while in 'OFF'
state and doing IOC_ENABLE without getting scheduled in exposes the
problem.
Further thinking about this problem, it occurred to me that we can
suffer a similar fate when we migrate an uncore event between CPUs.
The perf_event_install() on the 'new' CPU will do add_event_to_ctx()
which will reset all the time stamp, resulting in a subsequent
update_event_times() to overwrite the total_time_* fields with smaller
values.
Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch')
0 files changed, 0 insertions, 0 deletions