linux-kernel - Re: [PATCH 0/3 v2] nmi perf fixes

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Date:	Fri, 10 Sep 2010 14:13:28 +0200
From:	Stephane Eranian <eranian@...gle.com>
To:	Peter Zijlstra <peterz@...radead.org>
Cc:	Don Zickus <dzickus@...hat.com>, mingo@...e.hu,
	robert.richter@....com, gorcunov@...il.com, fweisbec@...il.com,
	linux-kernel@...r.kernel.org, ying.huang@...el.com,
	ming.m.lin@...el.com, yinghai@...nel.org, andi@...stfloor.org
Subject: Re: [PATCH 0/3 v2] nmi perf fixes

I think the broader issue here is that I think we should not have
so many subsystems hanging off of that die_register(). The NMI
should be for perf_events only. Many in there have nothing to do
with performance monitoring. They are mostly debug features.

On Fri, Sep 10, 2010 at 2:10 PM, Stephane Eranian <eranian@...gle.com> wrote:
> On Fri, Sep 10, 2010 at 1:41 PM, Peter Zijlstra <peterz@...radead.org> wrote:
>> On Thu, 2010-09-02 at 15:07 -0400, Don Zickus wrote:
>>> Fixes to allow unknown nmis to pass through the perf nmi handler instead
>>> of being swallowed.  Contains patches that are already in Ingo's tree.  Added
>>> here for completeness.  Based on ingo/tip
>>>
>>> Tested on intel/amd
>>>
>>> v2: patch cleanups and consolidation, no code changes
>>>
>>> Don Zickus (1):
>>>   perf, x86: Fix accidentally ack'ing a second event on intel perf
>>>     counter
>>>
>>> Peter Zijlstra (1):
>>>   perf, x86: Fix handle_irq return values
>>>
>>> Robert Richter (1):
>>>   perf, x86: Try to handle unknown nmis with an enabled PMU
>>>
>>>  arch/x86/kernel/cpu/perf_event.c       |   59 +++++++++++++++++++++++++-------
>>>  arch/x86/kernel/cpu/perf_event_intel.c |   15 +++++---
>>>  arch/x86/kernel/cpu/perf_event_p4.c    |    2 +-
>>>  3 files changed, 56 insertions(+), 20 deletions(-)
>>
>> Both Ingo and I are getting Dazed and confused on our AMD machines, it
>> started before yesterday (that is, after backing out all my recent
>> changes it still gets dazed), so I suspect this set.
>>
>> I'll look at getting a trace of the thing, but if any of you has a
>> bright idea...
>
> I still don't buy the back-to-back NMI thing. I suspect there is
> something else going on. I have continued to track it down.
> I got closer yesterday, until I ran into other issues. It may
> have to do with throttling. I am still trying to understanding
> why the OVF_STATUS does not match the check based on
> the counter values.
>
>>
>
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