From: Don Zickus <dzickus@redhat.com>
To: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: mingo@elte.hu, peterz@infradead.org, robert.richter@amd.com,
fweisbec@gmail.com, linux-kernel@vger.kernel.org,
ying.huang@intel.com, ming.m.lin@intel.com, yinghai@kernel.org,
andi@firstfloor.org, eranian@google.com
Subject: Re: [PATCH 1/3] perf, x86: Fix accidentally ack'ing a second event on intel perf counter
Date: Thu, 2 Sep 2010 16:00:21 -0400 [thread overview]
Message-ID: <20100902200021.GO4879@redhat.com> (raw)
In-Reply-To: <20100902192627.GB5538@lenovo>
On Thu, Sep 02, 2010 at 11:26:27PM +0400, Cyrill Gorcunov wrote:
> Lets assume 1 counters is triggered and global bit is set as well
>
> we have here
>
> status = intel_pmu_get_status();
>
> > perf_sample_data_init(&data, 0);
> >
> > @@ -728,6 +728,7 @@ static int intel_pmu_handle_irq(struct pt_regs *regs)
> >
> > loops = 0;
> > again:
> > + intel_pmu_ack_status(status);
>
> So here we write just being read value back to CTRL register and _if_ new
> overflow happened in this window we've cleared it without processing.
No, you have to write a '1' to clear. If a new bit is set after we read
it, then our 'status' var should have a '0' in that bit and thus will not
get cleared when we ack it.
Cheers,
Don
next prev parent reply other threads:[~2010-09-02 20:00 UTC|newest]
Thread overview: 117+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-09-02 19:07 [PATCH 0/3 v2] nmi perf fixes Don Zickus
2010-09-02 19:07 ` [PATCH 1/3] perf, x86: Fix accidentally ack'ing a second event on intel perf counter Don Zickus
2010-09-02 19:26 ` Cyrill Gorcunov
2010-09-02 20:00 ` Don Zickus [this message]
2010-09-02 20:36 ` Cyrill Gorcunov
2010-09-03 7:10 ` [tip:perf/urgent] " tip-bot for Don Zickus
2010-09-03 7:39 ` Yinghai Lu
2010-09-03 15:00 ` Don Zickus
2010-09-03 17:15 ` Yinghai Lu
2010-09-03 18:35 ` Don Zickus
2010-09-03 19:24 ` Yinghai Lu
2010-09-03 20:10 ` Don Zickus
2010-10-04 23:24 ` Yinghai Lu
2010-10-11 20:25 ` Don Zickus
2010-09-02 19:07 ` [PATCH 2/3] perf, x86: Try to handle unknown nmis with an enabled PMU Don Zickus
2010-09-03 7:11 ` [tip:perf/urgent] " tip-bot for Robert Richter
2010-09-02 19:07 ` [PATCH 3/3] perf, x86: Fix handle_irq return values Don Zickus
2010-09-03 7:10 ` [tip:perf/urgent] " tip-bot for Peter Zijlstra
2010-09-10 11:41 ` [PATCH 0/3 v2] nmi perf fixes Peter Zijlstra
2010-09-10 12:10 ` Stephane Eranian
2010-09-10 12:13 ` Stephane Eranian
2010-09-10 13:27 ` Don Zickus
2010-09-10 14:46 ` Ingo Molnar
2010-09-10 15:17 ` Robert Richter
2010-09-10 15:58 ` Peter Zijlstra
2010-09-10 16:41 ` Ingo Molnar
2010-09-10 16:42 ` Ingo Molnar
2010-09-10 16:37 ` Ingo Molnar
2010-09-10 16:51 ` Ingo Molnar
2010-09-10 15:56 ` [PATCH] x86: fix duplicate calls of the nmi handler Robert Richter
2010-09-10 16:15 ` Peter Zijlstra
2010-09-11 9:41 ` Ingo Molnar
2010-09-11 11:44 ` Robert Richter
2010-09-11 12:45 ` Ingo Molnar
2010-09-12 9:52 ` Robert Richter
2010-09-13 14:37 ` Robert Richter
2010-09-14 17:41 ` Robert Richter
2010-09-15 16:20 ` [PATCH] perf, x86: catch spurious interrupts after disabling counters Robert Richter
2010-09-15 16:36 ` Stephane Eranian
2010-09-15 17:00 ` Robert Richter
2010-09-15 17:32 ` Stephane Eranian
2010-09-15 18:44 ` Robert Richter
2010-09-15 19:34 ` Cyrill Gorcunov
2010-09-15 20:21 ` Stephane Eranian
2010-09-15 20:39 ` Cyrill Gorcunov
2010-09-15 22:27 ` Robert Richter
2010-09-16 14:51 ` Frederic Weisbecker
2010-09-15 16:46 ` Cyrill Gorcunov
2010-09-15 16:47 ` Stephane Eranian
2010-09-15 17:02 ` Cyrill Gorcunov
2010-09-15 17:28 ` Robert Richter
2010-09-15 17:40 ` Cyrill Gorcunov
2010-09-15 22:10 ` Robert Richter
2010-09-16 6:53 ` Cyrill Gorcunov
2010-09-16 17:34 ` Peter Zijlstra
2010-09-17 8:51 ` Robert Richter
2010-09-17 9:14 ` Peter Zijlstra
2010-09-17 13:06 ` Stephane Eranian
2010-09-20 8:41 ` Robert Richter
2010-09-24 0:02 ` Don Zickus
2010-09-24 3:18 ` Don Zickus
2010-09-24 10:03 ` Robert Richter
2010-09-24 13:38 ` Stephane Eranian
2010-09-30 12:33 ` Peter Zijlstra
2010-09-24 18:11 ` Don Zickus
2010-09-24 10:41 ` [tip:perf/urgent] perf, x86: Catch " tip-bot for Robert Richter
2010-09-29 12:26 ` Stephane Eranian
2010-09-29 12:53 ` Robert Richter
2010-09-29 12:54 ` Robert Richter
2010-09-29 13:13 ` Stephane Eranian
2010-09-29 13:28 ` Stephane Eranian
2010-09-29 15:01 ` Robert Richter
2010-09-29 15:12 ` Robert Richter
2010-09-29 15:27 ` Cyrill Gorcunov
2010-09-29 15:33 ` Stephane Eranian
2010-09-29 15:45 ` Cyrill Gorcunov
2010-09-29 15:51 ` Cyrill Gorcunov
2010-09-29 16:32 ` Robert Richter
2010-09-29 16:48 ` Cyrill Gorcunov
2010-09-29 16:00 ` Stephane Eranian
2010-09-29 17:09 ` Robert Richter
2010-09-29 17:41 ` Cyrill Gorcunov
2010-09-29 18:12 ` Don Zickus
2010-09-29 19:42 ` Stephane Eranian
2010-09-29 20:03 ` Don Zickus
2010-09-30 9:12 ` Robert Richter
2010-09-30 19:44 ` Don Zickus
2010-10-01 7:17 ` Robert Richter
[not found] ` <AANLkTimUyLaVaBigjm0-CwRsdh4UXWDiss2ffX53S+k_@mail.gmail.com>
2010-10-01 11:53 ` Stephane Eranian
2010-10-02 9:35 ` Robert Richter
2010-10-04 8:53 ` Stephane Eranian
2010-10-04 9:07 ` Andi Kleen
2010-10-04 17:28 ` Stephane Eranian
2010-09-29 16:31 ` Robert Richter
2010-09-29 16:22 ` Robert Richter
2010-09-29 19:01 ` Don Zickus
2010-09-29 13:39 ` Robert Richter
2010-09-29 13:56 ` Stephane Eranian
2010-09-29 14:00 ` Stephane Eranian
2010-10-02 9:50 ` Robert Richter
2010-10-02 17:40 ` Stephane Eranian
2010-09-29 15:02 ` Cyrill Gorcunov
2010-09-16 17:42 ` [PATCH] x86: fix duplicate calls of the nmi handler Peter Zijlstra
2010-09-16 20:18 ` Stephane Eranian
2010-09-17 7:09 ` Peter Zijlstra
2010-09-17 0:13 ` Huang Ying
2010-09-17 7:52 ` Peter Zijlstra
2010-09-17 8:13 ` Robert Richter
2010-09-17 8:37 ` Cyrill Gorcunov
2010-09-17 8:47 ` Huang Ying
2010-09-10 13:34 ` [PATCH 0/3 v2] nmi perf fixes Peter Zijlstra
2010-09-10 13:52 ` Peter Zijlstra
2010-09-13 8:55 ` Cyrill Gorcunov
2010-09-13 9:54 ` Stephane Eranian
2010-09-13 10:07 ` Cyrill Gorcunov
2010-09-13 10:10 ` Stephane Eranian
2010-09-13 10:12 ` Cyrill Gorcunov
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