From mboxrd@z Thu Jan  1 00:00:00 1970
From: Ingo Molnar <mingo@elte.hu>
Subject: Re: perf: prctl(PR_TASK_PERF_EVENTS_DISABLE) has no effect
Date: Sun, 29 Jan 2012 17:32:35 +0100
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To: Andrew Steets <asteets@rgmadvisors.com>
Cc: linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org, Peter Zijlstra <a.p.zijlstra@chello.nl>, Paul Mackerras <paulus@samba.org>, Arnaldo Carvalho de Melo <acme@ghostprotocols.net>


* Andrew Steets <asteets@rgmadvisors.com> wrote:

> On 1/28/12 6:01 AM, Ingo Molnar wrote:
> 
> >> prctl(PR_TASK_PERF_EVENTS_DISABLE) doesn't appear to 
> >> disable perf event counters.  Here is a demonstration 
> >> program:
> >
> > btw., what's your usecase?
> 
> I'm trying to profile a small section of a long-running 
> program.  I ran into trouble using call-graph recording and I 
> thought this might be an alternative way of getting what I was 
> after.

That usecase indeed makes sense. Peter, could we allow this for 
privileged tasks, depending on the perf_paranoia settings or 
such?

Thanks,

	Ingo