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From: Vince Weaver <vincent.weaver@maine.edu>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Vince Weaver <vincent.weaver@maine.edu>,
	Jiri Olsa <jolsa@redhat.com>,
	Stephane Eranian <eranian@google.com>,
	LKML <linux-kernel@vger.kernel.org>,
	Arnaldo Carvalho de Melo <acme@redhat.com>,
	mingo@elte.hu, Andi Kleen <ak@linux.intel.com>
Subject: Re: [RFC] perf/core: what is exclude_idle supposed to do
Date: Fri, 20 Apr 2018 10:18:04 -0400 (EDT)	[thread overview]
Message-ID: <alpine.DEB.2.21.1804201015250.22578@macbook-air> (raw)
In-Reply-To: <20180420083607.GG4064@hirez.programming.kicks-ass.net>

On Fri, 20 Apr 2018, Peter Zijlstra wrote:

> On Wed, Apr 18, 2018 at 11:10:20AM -0400, Vince Weaver wrote:
> > On Tue, 17 Apr 2018, Jiri Olsa wrote:
> > 
> > > On Mon, Apr 16, 2018 at 10:04:53PM +0000, Stephane Eranian wrote:
> > > > Hi,
> > > > 
> > > > I am trying to understand what the exclude_idle event attribute is supposed
> > > > to accomplish.
> > > > As per the definition in the header file:
> > > > 
> > > >     exclude_idle   :  1, /* don't count when idle */
> > > 
> > > AFAICS it's not implemented
> > 
> > so just to be completely clear hear, we're saying that the "exclude_idle" 
> > modifier has never done anything useful and still doesn't?
> 
> AFAICT it works on Power and possibly ARM.

at least some ARMs are a bit more honest about it than x86

ivybridge:
	Performance counter stats for '/bin/ls':
	1,368,162      instructions
	1,368,162      instructions:I

pi2/ARM cortex-A7
	Performance counter stats for '/bin/ls':
	1,910,083      instructions
	<not supported>      instructions:I

I'd fire up my Power8 machine to see but not sure it's worth the hassle 
and/or having to get out the ear protection.

Vince

  reply	other threads:[~2018-04-20 14:18 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-16 22:04 Stephane Eranian
2018-04-17  6:20 ` Jiri Olsa
2018-04-18 15:10   ` Vince Weaver
2018-04-20  8:36     ` Peter Zijlstra
2018-04-20 14:18       ` Vince Weaver [this message]
2018-04-20 16:51         ` Vince Weaver
2018-04-20 18:19           ` Stephane Eranian
2018-04-17 13:40 ` Arnaldo Carvalho de Melo
2018-04-20  8:35 ` Peter Zijlstra

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