From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: "Török Edwin" <edwintorok@gmail.com>
Cc: mingo@elte.hu, sandmann@daimi.au.dk,
linux-kernel@vger.kernel.org,
Steven Rostedt <rostedt@goodmis.org>,
Arjan van de Ven <arjan@infradead.org>
Subject: Re: [PATCH 4/4] Implement semaphore latency tracer
Date: Sun, 12 Oct 2008 21:13:06 +0200 [thread overview]
Message-ID: <1223838786.8634.8.camel@lappy.programming.kicks-ass.net> (raw)
In-Reply-To: <1223817124-27239-6-git-send-email-edwintorok@gmail.com>
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?
next prev parent reply other threads:[~2008-10-12 19:13 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-10-12 13:11 [PATCH 0/4] ftrace: add userspace stacktrace support and semaphore-latency tracer Török Edwin
2008-10-12 13:12 ` Török Edwin
2008-10-12 13:12 ` [PATCH 1/4] Add support for userspace stacktraces in tracing/iter_ctrl Török Edwin
2008-10-12 13:31 ` Frédéric Weisbecker
2008-10-12 13:53 ` Török Edwin
2008-10-13 8:02 ` Frédéric Weisbecker
2008-10-26 4:05 ` Frédéric Weisbecker
2008-10-26 7:03 ` Török Edwin
2008-10-26 15:06 ` Frédéric Weisbecker
2008-10-26 13:15 ` Frank Ch. Eigler
2008-10-26 13:29 ` Peter Zijlstra
2008-10-26 13:38 ` Török Edwin
2008-10-26 13:49 ` Frank Ch. Eigler
2008-10-27 16:03 ` Ingo Molnar
2008-10-27 16:16 ` Török Edwin
2008-10-12 13:12 ` [PATCH 2/4] Identify which executable object the userspace address belongs to Török Edwin
2008-10-12 13:12 ` [PATCH 3/4] add tracepoints in rwsem Török Edwin
2008-10-12 13:12 ` [PATCH 4/4] Implement semaphore latency tracer Török Edwin
2008-10-12 19:13 ` Peter Zijlstra [this message]
2008-10-12 20:10 ` Török Edwin
2008-10-22 15:28 ` Ingo Molnar
2008-10-22 15:41 ` Török Edwin
2008-10-22 15:48 ` Ingo Molnar
2008-10-22 17:22 ` Peter Zijlstra
2008-10-22 17:25 ` Török Edwin
2008-10-12 18:25 ` [PATCH 0/4] ftrace: add userspace stacktrace support and semaphore-latency tracer Steven Rostedt
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