Re: [PATCH] perf lock: track only specified threads

From: Frederic Weisbecker
Date: Thu May 06 2010 - 20:50:25 EST


On Thu, May 06, 2010 at 06:32:56PM +0900, Hitoshi Mitake wrote:
> I implemented the feature of tracking only specified threads to perf lock.
> With -t option, users can specify which threads should be tracked.
>
> Example of usage:
> | % sudo ./perf lock info -t # info -t is convenient with this feature
> | Thread ID: comm
> | 0: swapper
> | 1: init
> | 12: migration/3
> | 13: ksoftirqd/3
> | 27: events/0
> | 28: events/1
> | 29: events/2
> | 30: events/3
> | 31: events/4
> | 857: kondemand/0
> | 858: kondemand/1
> | 859: kondemand/2
> | ...
> | % sudo ./perf lock -t 27,28,29,30,31 report # track only these threads
> | Name acquired contended total wait (ns) max wait (ns) min wait (ns)



I'm not sure we want such per thread granularity filtering. I'm not
sure it will be very useful. But per process yeah.

And actually we should do that on tracing time rather than on post-processing.
This will lower the tracing overhead a lot.

Ideally I think we need:
./perf lock record ls -R /

This would trace locks taken by this instance of ls only, ie: drop the -a
if we pass a command line.

What do you think?

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