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

From: Namhyung Kim
Date: Thu Jul 11 2013 - 03:57:07 EST


On Wed, 10 Jul 2013 16:18:20 +0200, Jiri Olsa wrote:
> On Wed, Jun 26, 2013 at 04:14:09PM +0900, Namhyung Kim wrote:
>> From: Namhyung Kim <namhyung.kim@xxxxxxx>
>>
>> The -p (--pid) option enables to trace existing process by its pid.
>
> hi,
> I can't get any output from -p for live subcommand:
>
> [jolsa@krava perf]$ pgrep yes
> 6443
> [jolsa@krava perf]$ sudo ./perf ftrace live -p `pgrep yes`

Hmm... looks like it's stuck on polling the trace_pipe:

$ sudo strace ./perf ftrace -p `pgrep yes'
...
poll([{fd=3, events=POLLIN}], 1, 4294967295


Need to investigate it more.

Along with it, I found that I didn't close fd in
__write_tracing_file(). I'll fix it in the next spin too.

Thanks for the review and testing!
Namhyung
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