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

[Hitoshi Mitake]

On 05/07/10 09:49, Frederic Weisbecker wrote:
> 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?
>
>

Ah, I completely agree with your opinion :)
Even if user wants to append "-a",
  ./perf lock record -a ls -R /
is enough. "-a" should not in default set of arguments.

I'll send the patch to drop "-a" later.

Thanks,
	Hitoshi
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/