linux-kernel - Re: [PATCH] perf: fix the is_software

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Date:	Mon, 18 Jan 2010 13:07:49 +0100
From:	Frederic Weisbecker <fweisbec@...il.com>
To:	Peter Zijlstra <peterz@...radead.org>
Cc:	Stephane Eranian <eranian@...gle.com>,
	linux-kernel@...r.kernel.org, mingo@...e.hu, paulus@...ba.org,
	davem@...emloft.net, perfmon2-devel@...ts.sf.net
Subject: Re: [PATCH] perf: fix the is_software_event() definition

On Mon, Jan 18, 2010 at 12:53:36PM +0100, Peter Zijlstra wrote:
> On Mon, 2010-01-18 at 12:13 +0100, Peter Zijlstra wrote:
> > On Sun, 2010-01-17 at 15:12 +0100, Frederic Weisbecker wrote:
> > 
> > > You need to also call pmu->disable() if it is a software event,
> > > because a breakpoint needs to be unregistered in hardware level
> > > too.
> > 
> > breakpoint isn't a software pmu. But yeah, enable and disable need to
> > match.
> 
> That is, it shouldn't be a software pmu, because we assume software
> events can always be scheduled, whereas that's definitely not so for the
> breakpoint one.
> 
> Which seems to suggest the following
> 
> ---
> Subject: perf: fix the is_software_event() definition
> 
> When adding the breakpoint pmu Frederic forgot to exclude it from being
> a software event. While we're at it, make it an inclusive expression.
> 
> Signed-off-by: Peter Zijlstra <a.p.zijlstra@...llo.nl>



Agreed.

But then Stephane will need to update his patch and use
something else than is_software_event() to guess if an event
needs its pmu->enable/disable to be called.

A kind of helper that can tell: I am not handled by
hw_perf_group_sched_in()

But I suck too much in naming to propose something sane :)

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