Re: [PATCH 01/17] perf util: Save pid-cmdline mapping into tracingheader

From: Arnaldo Carvalho de Melo
Date: Wed Jul 31 2013 - 10:07:59 EST

Em Wed, Jul 31, 2013 at 09:51:54AM +0900, Namhyung Kim escreveu:
> 2013-07-30 ìí 10:28, Arnaldo Carvalho de Melo ì ê:
> >Em Tue, Jul 30, 2013 at 06:18:58PM +0900, Namhyung Kim escreveu:
> >>Current trace info data lacks the saved cmdline mapping which is
> >>needed for pevent to find out the comm of a task. Add this and bump
> >>up the version number so that perf can determine its presence when
> >>reading.

> >Can't we get this from the PERF_RECORD_COMM synthesized at the beginning
> >of the session + the kernel generated ones for new threads?

> >We would just call machine__find_thread() and use thread->comm, etc, no?

> Yes, I think it's doable. However it needs an additional perf event
> only to generate the COMM events. So I decided not to do it and

I don't think this is a problem, its in line with Ingo's suggestion of a
new perf ioctl to ask the kernel to generate PERF_RECORD_MMAP events for
existing threads.

- Arnaldo
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at