linux-kernel - Re: [PATCH 0/3] perf_event: enable overflow interrupts on KNC

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Message-ID: <20121017180753.GA7291@gmail.com>
Date:	Wed, 17 Oct 2012 20:07:53 +0200
From:	Ingo Molnar <mingo@...nel.org>
To:	Vince Weaver <vincent.weaver@...ne.edu>
Cc:	linux-kernel@...r.kernel.org,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Paul Mackerras <paulus@...ba.org>,
	Ingo Molnar <mingo@...hat.com>,
	Arnaldo Carvalho de Melo <acme@...stprotocols.net>,
	eranian@...il.com,
	"Meadows, Lawrence F" <lawrence.f.meadows@...el.com>
Subject: Re: [PATCH 0/3] perf_event: enable overflow interrupts on KNC


* Vince Weaver <vincent.weaver@...ne.edu> wrote:

> Hello
> 
> the following patchset enables overflow interrupts on Knights Corner,
> the initial KNC PMU driver that was included in 3.7-rc1 did not
> support this.

Nice!

> The first patch should be straightforward.
> The second should be too, but it relates to a problem with the p6 PMU
>     that I brought up in a separate thread.
> The third patch copies code over from the perf_event_intel.c interrupt
>     handler.  Unfortunately KNC and x86 architectural perfmon use
>     different MSR numbers.  The proper fix might be to make this
>     generic and have function vectors for the status/ack functions,
>     but since they are inline and probably performance critical
>     I took the easy way out and just duplicated the code.

The duplication looks pretty limited to me, so I don't think 
it's a problem.

How well tested is this on real hardware and how robust is the 
hardware with this? Since it's a new PMU driver for v3.7, and if 
these are reasonably well tested, then we could send these to 
Linus via perf/urgent, so that they don't miss and have to wait 
all the way to v3.8.

Thanks,

	Ingo
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