| Subject | Re: [PATCH 4/4] Implement semaphore latency tracer | From | Peter Zijlstra <> | Date | Sun, 12 Oct 2008 21:13:06 +0200 |
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On Sun, 2008-10-12 at 16:12 +0300, Török Edwin wrote: > Each time a down_read or down_write fails, a unique latency id is generated. > Later when someone releases the semaphore, it is blamed for the latency of all > tasks on the wait_list of the semaphore. > If you would group the output from latency_trace by the latency_id you get all those > who were contending on a lock, and the tasks that were holding the lock. > An entry in latency_trace has the format: > (latency_id) [semaphore_id] read|write > stacktrace <= stacktrace
What can this tracer do that latencytop cannot already do?
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