Re: [PATCH 06/19] perf ftrace: Add support for --pid option

From: Namhyung Kim
Date: Thu Jun 27 2013 - 10:13:09 EST


2013-06-27 (ë), 07:56 -0600, David Ahern:
> On 6/26/13 11:23 PM, Namhyung Kim wrote:
> > The pid filtering in ftrace is done via set_ftrace_pid file under the
> > tracing debugfs directory. IIRC It only supports process filtering not
> > thread filtering by iterating all threads in the kernel code. So --tid
> > option cannot be implemented as other perf commands.
> >
> > So I chose not to and assigned -t option to --tracer.
>
> Could that ever change? With the current code why call it pid in the
> option but assign it to target.tid? Seems a like a source for confusion

Hmm.. right. I did it in order not to do same iteration of the thread
group in user space. But now I think that it's just an unnecessary
optimization and can confuse readers.


> later. Would be better to just assign to target.pid and let the
> machinery do the right thing.

Will do.

Thanks,
Namhyung


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