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

From: Ingo Molnar
Date: Wed Oct 17 2012 - 14:07:49 EST

* Vince Weaver <vincent.weaver@xxxxxxxxx> 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.


> 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.


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