From mboxrd@z Thu Jan  1 00:00:00 1970
From: Arun Sharma <asharma@fb.com>
Subject: Re: Profiling sleep times?
Date: Mon, 10 Oct 2011 11:50:13 -0700
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To: avagin@gmail.com
Cc: Peter Zijlstra <peterz@infradead.org>, linux-perf-users@vger.kernel.org, acme@ghostprotocols.net, mingo@elte.hu, Stephane Eranian <eranian@google.com>, Frederic Weisbecker <fweisbec@gmail.com>

On 10/7/11 6:45 PM, avagin@gmail.com wrote:
>> Andrew, are you already working on user space patches?
>
> Yes, I'm working. I've attached the draft version.

Generally I'm happy with the direction of these patches. For doing wall 
time based profiling we'll need support in perf inject to merge sleep + 
cycles events.

Re: examples of why one might need histograms based on various fields in 
a dynamic kernel probe:

I might want to add a probe such as:

perf probe --add 'sys_read fd=%di'
perf probe --add 'sys_read%return bytes=$retval'

and expect to find stack traces that are responsible for most I/O calls 
based on bytes vs fd vs number of syscalls.

  -Arun