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Message-Id: <1239052864.4557.62.camel@laptop>
Date: Mon, 06 Apr 2009 23:21:04 +0200
From: Peter Zijlstra <peterz@...radead.org>
To: Corey Ashford <cjashfor@...ux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@...e.hu>, Paul Mackerras <paulus@...ba.org>,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH 5/6] perf_counter: add more context information
On Mon, 2009-04-06 at 14:15 -0700, Corey Ashford wrote:
>
> Peter Zijlstra wrote:
> > On Mon, 2009-04-06 at 13:16 -0700, Corey Ashford wrote:
> >
> >>>> One downside of this approach is that you if you specify "no header"
> >>>> (currently not possible, but maybe later?), you will not be able to get
> >>>> the level bits.
> >>> Would this be desirable?
> >
> >> I think it would. For one use case I'm working on right now, simple
> >> profiling, all I need are ip's. If I could omit the header, that would
> >> reduce the frequency of sigio's by a factor of three, and make it faster
> >> to read up the ip's when the SIGIO's occur.
> >
> > Self-profiling?
> >
> > So you're interested in getting the smallest possible record size, that
> > would still be 2 u64, right? Otherwise you don't get the IP context that
> > started this.
> >
> >
>
> Self-profiling mainly, yes. PAPI specs an ability for remote monitoring
> of processes and threads, but I think it's only partially implemented.
>
> So when you are talking about IP context, you mean pid/tid?
Ah, we called it level before, the hv/kernel/user thing. For remote
profiling you'd want to have the mmap thing too.
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