From: Don Zickus <dzickus@redhat.com>
To: Jason Wessel <jason.wessel@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@elte.hu>,
Robert Richter <robert.richter@amd.com>,
ying.huang@intel.com, Andi Kleen <andi@firstfloor.org>,
LKML <linux-kernel@vger.kernel.org>,
Frederic Weisbecker <fweisbec@gmail.com>
Subject: Re: [V2 PATCH 0/6] x86, NMI: give NMI handler a face-lift
Date: Thu, 18 Nov 2010 15:08:07 -0500 [thread overview]
Message-ID: <20101118200807.GC8131@redhat.com> (raw)
In-Reply-To: <4CE583D0.8050407@windriver.com>
On Thu, Nov 18, 2010 at 01:51:44PM -0600, Jason Wessel wrote:
> > So the problem is when the nmi watchdog is enabled, the perf event is
> > 'active' and thus tries to read the counter value. Because it is always
> > zero, perf just assumes the counter overflowed and the NMI is his.
> >
> > Not sure how to fix it yet, other than include the logic that detects we
> > are on a guest and disable perf??
> >
> >
>
> I highly doubt we want to disable perf. I would rather use the source
> and fix the nmi emulation in KVM/Qemu after we hear back the results
Well I think Peter does not have a positive opinion about emulating perf
inside a guest. Nor are the KVM folks having much success in doing so.
Just to clarify, perf counter emulation is _not_ implemented in kvm.
Therefore disabling perf in the guest makes sense until someone gets
around to actually writing the emulation code for perf in a guest. :-)
Cheers,
Don
next prev parent reply other threads:[~2010-11-18 20:08 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-11-12 14:43 [V2 PATCH 0/6] x86, NMI: give NMI handler a face-lift Don Zickus
2010-11-12 14:43 ` [PATCH 1/6] x86, NMI: Add NMI symbol constants and rename memory parity to PCI SERR Don Zickus
2010-11-12 14:43 ` [PATCH 2/6] x86, NMI: Add touch_nmi_watchdog to io_check_error delay Don Zickus
2010-11-12 14:43 ` [PATCH 3/6] x86, NMI: Rewrite NMI handler Don Zickus
2010-11-12 14:43 ` [PATCH 4/6] x86, NMI: Remove DIE_NMI_IPI and add priorties to handlers Don Zickus
2010-11-12 14:43 ` [PATCH 5/6] x86, NMI: Allow NMI reason io port (0x61) to be processed on any CPU Don Zickus
2010-11-12 14:43 ` [PATCH 6/6] x86, NMI: Remove do_nmi_callback logic Don Zickus
2010-11-12 15:05 ` [V2 PATCH 0/6] x86, NMI: give NMI handler a face-lift Jason Wessel
2010-11-12 15:42 ` Don Zickus
2010-11-12 15:55 ` Jason Wessel
2010-11-12 16:11 ` Don Zickus
2010-11-12 16:34 ` Jason Wessel
2010-11-12 17:27 ` Don Zickus
2010-11-16 18:43 ` Don Zickus
2010-11-16 20:04 ` Jason Wessel
2010-11-18 8:05 ` Ingo Molnar
2010-11-18 12:47 ` Jason Wessel
2010-11-18 13:17 ` Peter Zijlstra
2010-11-18 14:32 ` Don Zickus
2010-11-18 15:18 ` Jason Wessel
2010-11-18 15:38 ` Peter Zijlstra
2010-11-18 19:32 ` Don Zickus
2010-11-18 19:51 ` Jason Wessel
2010-11-18 20:04 ` Peter Zijlstra
2010-11-18 20:08 ` Don Zickus [this message]
2010-11-18 20:11 ` Cyrill Gorcunov
2010-11-18 20:52 ` Don Zickus
2010-11-18 21:01 ` Cyrill Gorcunov
2010-11-18 21:16 ` Don Zickus
2010-11-18 21:26 ` Cyrill Gorcunov
2010-11-18 20:28 ` Cyrill Gorcunov
2010-11-18 20:39 ` Cyrill Gorcunov
2010-11-18 21:02 ` Don Zickus
2010-11-18 21:19 ` Cyrill Gorcunov
2010-11-18 20:30 ` Peter Zijlstra
2010-11-19 16:59 ` Don Zickus
2010-11-19 18:25 ` Peter Zijlstra
2010-11-19 22:59 ` Don Zickus
2010-11-19 23:09 ` Peter Zijlstra
2010-11-19 23:30 ` Jason Wessel
2010-11-22 14:22 ` Don Zickus
2010-11-22 14:22 ` Don Zickus
2010-11-22 14:29 ` Peter Zijlstra
2010-11-18 20:04 ` Cyrill Gorcunov
2010-11-18 21:56 ` Cyrill Gorcunov
2010-11-18 21:58 ` Cyrill Gorcunov
2010-11-18 22:15 ` Cyrill Gorcunov
2010-11-18 22:24 ` Jason Wessel
2010-11-18 22:27 ` Cyrill Gorcunov
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