Messages in this thread | | | Date | Thu, 12 Aug 2010 09:52:33 -0400 | From | Don Zickus <> | Subject | Re: [PATCH -v2] perf, x86: try to handle unknown nmis with running perfctrs |
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On Thu, Aug 12, 2010 at 12:00:58AM +0200, Robert Richter wrote: > I was debuging this a little more, see version 2 below. > > -Robert > > -- > > From 8bb831af56d118b85fc38e0ddc2e516f7504b9fb Mon Sep 17 00:00:00 2001 > From: Robert Richter <robert.richter@amd.com> > Date: Thu, 5 Aug 2010 16:19:59 +0200 > Subject: [PATCH] perf, x86: try to handle unknown nmis with running perfctrs > > When perfctrs are running it is valid to have unhandled nmis, two > events could trigger 'simultaneously' raising two back-to-back > NMIs. If the first NMI handles both, the latter will be empty and daze > the CPU. > > The solution to avoid an 'unknown nmi' massage in this case was simply > to stop the nmi handler chain when perfctrs are runnning by stating > the nmi was handled. This has the drawback that a) we can not detect > unknown nmis anymore, and b) subsequent nmi handlers are not called. > > This patch addresses this. Now, we check this unknown NMI if it could > be a perfctr back-to-back NMI. Otherwise we pass it and let the kernel > handle the unknown nmi.
Seems to cover my concerns. Great work!
ACK
Cheers, Don
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