Re: [RFC] x86, perf: high volume of events produces a flood ofunknown NMIs

From: Don Zickus
Date: Wed Apr 20 2011 - 15:12:56 EST


On Wed, Apr 20, 2011 at 10:47:51PM +0400, Cyrill Gorcunov wrote:
> > Or perhaps we don't care about this because in the end perf can't even
> > capture the data without spitting out a CPU Overload message.
> >
> > Thoughts?
> >
>
> Hi Don, just a thought -- since pmi masks lvtpc we could read it and check if it's
> masked or no, though I fear it is quite time consuming operation in compare with
> frames :( (hmm, intel spec mentions only p4 and xeon as masking lvtpc)

Been there, tried that. It seems to be masked a large majority of the
time, even when the NMIs don't appear to be back-to-back.

Cheers,
Don
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/