Re: [RFC 2/2] x86_64, mm: Reinsert the absent memory

[Nathan Zimmer]

On 06/26/2013 10:58 AM, Ingo Molnar wrote:
> * Nathan Zimmer <nzimmer@xxxxxxx> wrote:
>
> > On 06/26/2013 10:12 AM, Dave Hansen wrote:
> > > On 06/26/2013 07:49 AM, Nathan Zimmer wrote:
> > > > My guess it is the NMIs overwhelming the system but I have not found a good way
> > > > to profile perf gone wild so it is only a guess.
> > > I've got an 80-core system and the symptoms sound similar to perf issues
> > > I'm seeing.  Dropping the sample rate helped for me, and there's a patch
> > > in -tip at the moment to do it automatically:
> > >
> > > > http://git.kernel.org/cgit/linux/kernel/git/tip/tip.git/commit/?id=14c63f17b1fde5a575a28e96547a22b451c71fb5
> > > Looks like you've also found that debugging NMIs is fun. :)
> > More fun then one person can handle.
> > I'll have to take this patch for a spin.
> Please try latest -tip:master, there's a series of patches from Dave that
> address this problem category.
>
> Does it only happen with -g, or with regular perf record and/or with perf
> top as well?
>
> Thanks,
>
> 	Ingo

It happens in all those cases, but I notice it most when doing a perf 
record -g -a
I'll try the tip series and see how it compares.

Thanks
    Nate
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