From: Don Zickus <dzickus@redhat.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Robert Richter <robert.richter@amd.com>,
Lin Ming <ming.m.lin@intel.com>, Ingo Molnar <mingo@elte.hu>,
Cyrill Gorcunov <gorcunov@gmail.com>,
"fweisbec@gmail.com" <fweisbec@gmail.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"Huang, Ying" <ying.huang@intel.com>
Subject: Re: A question of perf NMI handler
Date: Wed, 4 Aug 2010 11:45:52 -0400 [thread overview]
Message-ID: <20100804154552.GR3353@redhat.com> (raw)
In-Reply-To: <1280934161.1923.1294.camel@laptop>
On Wed, Aug 04, 2010 at 05:02:41PM +0200, Peter Zijlstra wrote:
> So then the first interrupt will see 3+ overflows, return 3+, and will
> thus eat 2+ NMIs, only one of which will be the pending interrupt,
> leaving 1+ NMIs from other sources to consume unhandled.
>
> In which case Yinghai will have to press his NMI button 2+ times before
> it registers.
>
> That said, that might be a better situation than always consuming
> unknown NMIs..
Well if the worse case scenario is only one extra NMI, then I can change
the logic in my patch to eat a max of 1 possible NMI instead of 2 as in the
example you gave above.
It still won't be 100% accurate but how often are people running perf
where they need 4 counters, have to hit an external nmi button or run into
broken firmware all at the same time? :-)
Cheers,
Don
next prev parent reply other threads:[~2010-08-04 15:46 UTC|newest]
Thread overview: 85+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-08-04 9:21 A question of perf NMI handler Lin Ming
2010-08-04 9:50 ` Peter Zijlstra
2010-08-04 10:01 ` Robert Richter
2010-08-04 10:24 ` Peter Zijlstra
2010-08-04 10:29 ` Robert Richter
2010-08-04 14:00 ` Don Zickus
2010-08-04 14:11 ` Peter Zijlstra
2010-08-04 14:52 ` Don Zickus
2010-08-04 15:02 ` Peter Zijlstra
2010-08-04 15:18 ` Cyrill Gorcunov
2010-08-04 15:50 ` Don Zickus
2010-08-04 16:10 ` Cyrill Gorcunov
2010-08-04 16:20 ` Don Zickus
2010-08-04 16:39 ` Cyrill Gorcunov
2010-08-04 18:48 ` Robert Richter
2010-08-04 19:22 ` Andi Kleen
2010-08-04 19:26 ` Cyrill Gorcunov
2010-08-06 6:52 ` Robert Richter
2010-08-06 14:21 ` Don Zickus
2010-08-09 19:48 ` [PATCH] perf, x86: try to handle unknown nmis with running perfctrs Robert Richter
2010-08-09 20:02 ` Cyrill Gorcunov
2010-08-10 7:42 ` Robert Richter
2010-08-10 16:16 ` Cyrill Gorcunov
2010-08-10 16:41 ` Robert Richter
2010-08-10 17:24 ` Cyrill Gorcunov
2010-08-10 19:05 ` Robert Richter
2010-08-10 19:24 ` Cyrill Gorcunov
2010-08-12 13:24 ` Robert Richter
2010-08-12 14:31 ` Cyrill Gorcunov
2010-08-10 20:48 ` Don Zickus
2010-08-11 2:44 ` Frederic Weisbecker
2010-08-11 11:10 ` Robert Richter
2010-08-11 12:44 ` Don Zickus
2010-08-11 14:03 ` Robert Richter
2010-08-11 14:32 ` Don Zickus
2010-08-13 4:37 ` Frederic Weisbecker
2010-08-13 8:22 ` Robert Richter
2010-08-14 1:28 ` Frederic Weisbecker
2010-08-14 2:29 ` Robert Richter
2010-08-11 12:39 ` Don Zickus
2010-08-11 3:19 ` Huang Ying
2010-08-11 12:36 ` Don Zickus
2010-08-16 14:37 ` Peter Zijlstra
2010-08-11 22:00 ` [PATCH -v2] " Robert Richter
2010-08-12 13:10 ` Robert Richter
2010-08-12 18:21 ` Don Zickus
2010-08-16 7:37 ` Robert Richter
2010-08-12 13:52 ` Don Zickus
2010-08-13 4:25 ` Frederic Weisbecker
2010-08-16 14:48 ` Peter Zijlstra
2010-08-16 16:27 ` Cyrill Gorcunov
2010-08-16 17:16 ` Robert Richter
2010-08-16 19:06 ` Cyrill Gorcunov
2010-08-16 19:13 ` Peter Zijlstra
2010-08-16 19:18 ` Cyrill Gorcunov
2010-08-16 22:55 ` Robert Richter
2010-08-17 15:23 ` Cyrill Gorcunov
2010-08-17 15:22 ` [PATCH -v3] " Robert Richter
2010-08-17 16:17 ` Cyrill Gorcunov
2010-08-19 10:45 ` Peter Zijlstra
2010-08-19 12:39 ` Robert Richter
2010-08-19 14:12 ` Don Zickus
2010-08-19 14:27 ` Peter Zijlstra
2010-08-19 15:20 ` Don Zickus
2010-08-19 17:43 ` Cyrill Gorcunov
2010-08-19 17:53 ` Peter Zijlstra
2010-08-19 21:58 ` Don Zickus
2010-08-20 8:50 ` Peter Zijlstra
2010-08-20 1:50 ` Don Zickus
2010-08-20 8:16 ` Ingo Molnar
2010-08-20 10:04 ` Peter Zijlstra
2010-08-20 10:30 ` Cyrill Gorcunov
2010-08-20 12:39 ` Don Zickus
2010-08-20 13:27 ` Ingo Molnar
2010-08-20 13:51 ` Don Zickus
2010-08-20 14:17 ` Ingo Molnar
2010-08-20 20:45 ` Cyrill Gorcunov
2010-08-24 21:48 ` Don Zickus
2010-08-20 8:36 ` Robert Richter
2010-08-20 14:17 ` [tip:perf/urgent] perf, x86: Fix handle_irq return values tip-bot for Peter Zijlstra
2010-08-20 14:17 ` [tip:perf/urgent] perf, x86: Try to handle unknown nmis with an enabled PMU tip-bot for Robert Richter
2010-08-06 15:35 ` A question of perf NMI handler Andi Kleen
2010-08-04 15:45 ` Don Zickus [this message]
2010-08-06 15:37 ` Andi Kleen
2010-08-04 13:54 ` Don Zickus
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