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From: Hedi Berriche <hedi@sgi.com>
To: Petr Tesarik <ptesarik@suse.cz>
Cc: linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org,
	Tony Luck <tony.luck@intel.com>
Subject: Re: Serious problem with ticket spinlocks on ia64
Date: Fri, 27 Aug 2010 13:48:02 +0000	[thread overview]
Message-ID: <20100827134802.GX18967@zorg.emea.sgi.com> (raw)
In-Reply-To: <201008271537.35709.ptesarik@suse.cz>

On Fri, Aug 27, 2010 at 14:38 Petr Tesarik wrote:
| Hi everybody,
| 
| SGI has recently experienced failures with the new ticket spinlock
| implementation. Hedi Berriche sent me a simple test case that can
| trigger the failure on the siglock.

One more fact, the problem was introduced by commit

    commit 9d40ee200a527ce08ab8c793ba8ae3e242edbb0e
    Author: Tony Luck <tony.luck@intel.com>
    Date:   Wed Oct 7 10:54:19 2009 -0700

        [IA64] Squeeze ticket locks back into 4 bytes.

Reverting the patch makes the problem go away.

IOW, and as far as testing shows, the first incarnation of the ticket locks
implementation on IA64 (commit 2c8696), the one that used 8 bytes, does not
exhibit this problem.

Cheers,
Hedi.
-- 
Hedi Berriche
Global Product Support
http://www.sgi.com/support

  reply	other threads:[~2010-08-27 13:48 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-08-27 13:37 Serious problem with ticket spinlocks on ia64 Petr Tesarik
2010-08-27 13:48 ` Hedi Berriche [this message]
2010-08-27 14:09   ` Petr Tesarik
2010-08-27 14:31     ` Hedi Berriche
2010-08-27 14:40       ` Petr Tesarik
2010-08-27 14:52         ` Hedi Berriche
2010-08-27 16:37           ` Petr Tesarik
2010-08-27 16:08 ` Luck, Tony
2010-08-27 17:16   ` Petr Tesarik
2010-08-27 18:20     ` Hedi Berriche
2010-08-27 19:40     ` Petr Tesarik
2010-08-27 20:29   ` Luck, Tony
2010-08-27 20:41     ` Petr Tesarik
2010-08-27 21:03     ` Petr Tesarik
2010-08-27 21:11       ` Luck, Tony
2010-08-27 22:13         ` Petr Tesarik
2010-08-27 23:26           ` Luck, Tony
2010-08-27 23:55             ` Luck, Tony
2010-08-28  0:28               ` Hedi Berriche
2010-08-28  5:01                 ` Luck, Tony
2010-08-30 18:17                   ` Luck, Tony
2010-08-30 21:41                     ` Petr Tesarik
2010-08-30 22:43                       ` Tony Luck
2010-08-31 22:17                         ` Tony Luck
2010-09-01 23:09                           ` Tony Luck
2010-09-02  0:26                             ` Hedi Berriche
2010-09-03  0:06                               ` Tony Luck
2010-09-03  9:04                                 ` Petr Tesarik
2010-09-03 14:35                                   ` Petr Tesarik
2010-09-03 14:52                                     ` Petr Tesarik
2010-09-03 15:50                                       ` Tony Luck
2010-09-06 14:47                                         ` Petr Tesarik
2010-09-07 13:17                                           ` Petr Tesarik
2010-09-07 17:35                                             ` Tony Luck
2010-09-08 15:55                                               ` Tony Luck
2010-09-10  2:55                                     ` Dave Jones

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