From: Cyrill Gorcunov <gorcunov@gmail.com>
To: Stephane Eranian <eranian@google.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>,
Don Zickus <dzickus@redhat.com>, Ingo Molnar <mingo@elte.hu>,
Lin Ming <ming.m.lin@intel.com>,
Arnaldo Carvalho de Melo <acme@redhat.com>,
Frederic Weisbecker <fweisbec@gmail.com>,
Vince Weaver <vweaver1@eecs.utk.edu>,
lkml <linux-kernel@vger.kernel.org>
Subject: Re: [RFC -tip] perf, x86: Add PERF_COUNT_HW_NMI_WATCHDOG event v2
Date: Tue, 21 Jun 2011 21:02:29 +0400 [thread overview]
Message-ID: <20110621170229.GD21641@sun> (raw)
In-Reply-To: <20110621164820.GC21641@sun>
On Tue, Jun 21, 2011 at 08:48:20PM +0400, Cyrill Gorcunov wrote:
...
>
> The key here is that we use that named non-sleeping ticks (as oprofile
> did) for nmi-watchdog and it allows us to free "cpu-cycles" counter for
> user needs. Of course we pick up one counter for this but it doesn't intersect
> with "cpu-cycles" counter (because counters are grouped and can count only
> specified events in each group). Stepane, should I post more details?
>
> Cyrill
Stephane, I think I have a shorter explanation -- the counter is still borrowed
(there is no magic ;) but this counter is less loaded than anything else (in
terms of restrictions) so since CPU cycles is a way more popular now it's allowed
to count them simultaneously with nmi-watchdog, but again -- this means
another set of events can't work and if (for some reason) user needs this counter
he has to disable nmi-watchdog.
Cyrill
next prev parent reply other threads:[~2011-06-21 17:02 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-04-28 15:37 [RFC -tip] perf, x86: Add PERF_COUNT_HW_NMI_WATCHDOG event v2 Cyrill Gorcunov
2011-06-21 15:23 ` Don Zickus
2011-06-21 15:40 ` Cyrill Gorcunov
2011-06-21 15:58 ` Peter Zijlstra
2011-06-21 16:13 ` Cyrill Gorcunov
2011-06-21 16:20 ` Stephane Eranian
2011-06-21 16:48 ` Cyrill Gorcunov
2011-06-21 17:02 ` Cyrill Gorcunov [this message]
2011-06-21 17:10 ` Stephane Eranian
2011-06-21 17:23 ` Cyrill Gorcunov
2011-06-21 17:26 ` Stephane Eranian
2011-06-21 17:54 ` Cyrill Gorcunov
2011-06-21 18:06 ` Stephane Eranian
2011-06-21 18:32 ` Cyrill Gorcunov
2011-06-22 8:27 ` Cyrill Gorcunov
2011-06-22 9:21 ` Cyrill Gorcunov
2011-06-23 6:48 ` Cyrill Gorcunov
2011-06-23 9:40 ` Stephane Eranian
2011-06-23 9:54 ` Cyrill Gorcunov
2011-06-23 11:07 ` Cyrill Gorcunov
2011-06-23 11:40 ` Don Zickus
2011-06-23 11:44 ` Stephane Eranian
2011-06-23 11:53 ` Cyrill Gorcunov
2011-06-23 12:03 ` Stephane Eranian
2011-06-23 12:07 ` Cyrill Gorcunov
2011-06-23 12:26 ` Cyrill Gorcunov
2011-06-23 12:31 ` Stephane Eranian
2011-06-23 12:34 ` Cyrill Gorcunov
2011-06-23 11:51 ` Cyrill Gorcunov
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