Re: [PATCH] perf, x86: P4 PMU -- Fix unflagged overflows test

From: Cyrill Gorcunov
Date: Mon Feb 07 2011 - 12:22:34 EST


On 02/06/2011 10:21 PM, Cyrill Gorcunov wrote:
> On 02/04/2011 07:59 PM, Don Zickus wrote:
>> On Fri, Feb 04, 2011 at 03:17:28PM +0300, Cyrill Gorcunov wrote:
>>> Please apply it, sorry for non-inlined patch (have a web access only at moment).
>>>
>>> Note that I've tested the patch on non-HT machine so if someone have HT'ed one
>>> -- it would be great to test the patch there.
>>
>> Hmm. For some reason, when I enable the kgdb testsuite, the box fails to
>> boot with hardlockup issues. It seems like the code is swallowing the
>> NMIs? I basically applied this patch on top of 2.6.38-rc3 and ran it on my
>> Xeon box (p4 w/HT).
>>
>> Cheers,
>> Don
>
> Don, I hope to get access to p4 machine tomorrow and investigate this issue
> (didn't manage to read kgdb code this weekend). Sorry for delay.
>

Just for info -- I've tested the patch on p4 machine with kgdb bootup tests
and results are somehow strange. If I disable nmi-watchdog the tests passes
fine and i'm able to run perf top (or anything related). Same time if I leave
nmi-watchdog enabled by default the borrowed event reported, kgdb tests passes
but nmi-watchdog never fires (ie I see nmi irq counter remains zero). So I've added
debug prints and found that counter reaches positive values and didn't issues
nmi at all. All in one -- i'm still investigating this issue unfortunatelly
the kernel build procedure sometime takes hours on this machine (even with
ccache enabled) so it goes a way slower then I expected :(
--
Cyrill
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