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From: David Ahern <dsahern@gmail.com>
To: Dave Jones <davej@redhat.com>,
	Dave Hansen <dave.hansen@intel.com>,
	Ingo Molnar <mingo@kernel.org>,
	Markus Trippelsdorf <markus@trippelsdorf.de>,
	Thomas Gleixner <tglx@linutronix.de>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Linux Kernel <linux-kernel@vger.kernel.org>,
	Peter Anvin <hpa@zytor.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Dave Hansen <dave.hansen@linux.intel.com>
Subject: Re: Yet more softlockups.
Date: Fri, 12 Jul 2013 12:07:28 -0600	[thread overview]
Message-ID: <51E045E0.8020702@gmail.com> (raw)
In-Reply-To: <20130712175028.GA11036@redhat.com>

On 7/12/13 11:50 AM, Dave Jones wrote:

> Given you can run trinity long enough that you hit this however, makes me
> think you won't be able to triger the bug I'm talking about.
> Perhaps virtualised perf counters are somehow immune to this problem, because
> on bare-metal, it literally takes seconds.

I can generate the message it just does not lock up:

...
[  131.837129] perf samples too long (35849 > 35714), lowering 
kernel.perf_event_max_sample_rate to 4000
...
[  237.271170] INFO: NMI handler (perf_event_nmi_handler) took too long 
to run: 57900.001 msecs


And Dave Hansen: I think nmi.c has the same do_div problem as 
kernel/events/core.c that Stephane fixed. Your patch has:

         whole_msecs = do_div(delta, (1000 * 1000));
         decimal_msecs = do_div(delta, 1000) % 1000;

David

  reply	other threads:[~2013-07-12 18:07 UTC|newest]

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-07-04  1:55 scheduling while atomic & hang Dave Jones
2013-07-04  2:49 ` Linus Torvalds
2013-07-04  4:43   ` H. Peter Anvin
2013-07-04  7:49   ` Dave Jones
2013-07-04 17:22     ` Linus Torvalds
2013-07-10 20:54     ` J. Bruce Fields
2013-07-04 18:08   ` H. Peter Anvin
2013-07-05  6:51     ` Ingo Molnar
2013-07-05  7:19       ` Frederic Weisbecker
2013-07-05 10:05         ` Ingo Molnar
2013-07-05 19:27       ` Linus Torvalds
2013-07-06  8:02         ` Frederic Weisbecker
2013-07-06  8:07           ` Ingo Molnar
2013-07-05 14:38   ` Yet more softlockups Dave Jones
2013-07-05 15:15     ` Thomas Gleixner
2013-07-05 16:00       ` Dave Jones
2013-07-05 16:02         ` Thomas Gleixner
2013-07-05 16:41           ` H. Peter Anvin
2013-07-05 18:20             ` Seiji Aguchi
2013-07-05 22:21               ` Thomas Gleixner
2013-07-06  7:24         ` Ingo Molnar
2013-07-07  0:24           ` Dave Jones
2013-07-10 15:13           ` Dave Jones
2013-07-10 15:20             ` Markus Trippelsdorf
2013-07-10 15:40               ` Dave Jones
2013-07-12 10:31                 ` Ingo Molnar
2013-07-12 15:38                   ` Dave Hansen
2013-07-12 15:45                     ` Dave Jones
2013-07-12 15:55                       ` Dave Hansen
2013-07-12 17:00                         ` Dave Jones
2013-07-12 17:12                       ` David Ahern
2013-07-12 17:18                         ` Dave Jones
2013-07-12 17:40                           ` David Ahern
2013-07-12 17:50                             ` Dave Jones
2013-07-12 18:07                               ` David Ahern [this message]
2013-07-12 18:22                                 ` Dave Hansen
2013-07-12 20:13                                 ` Dave Hansen
2013-07-13  1:40                       ` Vince Weaver
2013-07-10 15:39             ` Vince Weaver
2013-07-10 15:45               ` Dave Jones
2013-07-10 21:54               ` Dave Jones

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