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From: Petr Tesarik <ptesarik@suse.cz>
To: "Luck, Tony" <tony.luck@intel.com>
Cc: "linux-ia64@vger.kernel.org" <linux-ia64@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Hedi Berriche <hedi@sgi.com>
Subject: Re: Serious problem with ticket spinlocks on ia64
Date: Fri, 27 Aug 2010 20:41:14 +0000	[thread overview]
Message-ID: <201008272241.15735.ptesarik@suse.cz> (raw)
In-Reply-To: <987664A83D2D224EAE907B061CE93D53015D91D3B7@orsmsx505.amr.corp.intel.com>

On Friday 27 of August 2010 22:29:41 Luck, Tony wrote:
> > If this is a memory ordering problem (and that seems quite plausible)
> > then a liberal sprinkling of "ia64_mf()" calls throughout the spinlock
> > routines would probably make it go away.
>
> I think I take this back ... if it were a memory ordering problem, then
> it could show up any time - not just at wrap-around.

Well, I wasn't originally sure if it only happens at wrap-around. OTOH I've 
now modified my tests, so that they would also catch any other badness, and I 
still only got another two failures after wrap-around.

From looking at the traces, I'm afraid this smells like another Itanium 
erratum. I'm now trying to write a minimal test case...

Petr Tesarik

WARNING: multiple messages have this Message-ID (diff)
From: Petr Tesarik <ptesarik@suse.cz>
To: "Luck, Tony" <tony.luck@intel.com>
Cc: "linux-ia64@vger.kernel.org" <linux-ia64@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Hedi Berriche <hedi@sgi.com>
Subject: Re: Serious problem with ticket spinlocks on ia64
Date: Fri, 27 Aug 2010 22:41:14 +0200	[thread overview]
Message-ID: <201008272241.15735.ptesarik@suse.cz> (raw)
In-Reply-To: <987664A83D2D224EAE907B061CE93D53015D91D3B7@orsmsx505.amr.corp.intel.com>

On Friday 27 of August 2010 22:29:41 Luck, Tony wrote:
> > If this is a memory ordering problem (and that seems quite plausible)
> > then a liberal sprinkling of "ia64_mf()" calls throughout the spinlock
> > routines would probably make it go away.
>
> I think I take this back ... if it were a memory ordering problem, then
> it could show up any time - not just at wrap-around.

Well, I wasn't originally sure if it only happens at wrap-around. OTOH I've 
now modified my tests, so that they would also catch any other badness, and I 
still only got another two failures after wrap-around.

>From looking at the traces, I'm afraid this smells like another Itanium 
erratum. I'm now trying to write a minimal test case...

Petr Tesarik

  reply	other threads:[~2010-08-27 20:41 UTC|newest]

Thread overview: 72+ 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 13:37 ` Petr Tesarik
2010-08-27 13:48 ` Hedi Berriche
2010-08-27 13:48   ` Hedi Berriche
2010-08-27 14:09   ` Petr Tesarik
2010-08-27 14:09     ` Petr Tesarik
2010-08-27 14:31     ` Hedi Berriche
2010-08-27 14:31       ` Hedi Berriche
2010-08-27 14:40       ` Petr Tesarik
2010-08-27 14:40         ` Petr Tesarik
2010-08-27 14:52         ` Hedi Berriche
2010-08-27 14:52           ` Hedi Berriche
2010-08-27 16:37           ` Petr Tesarik
2010-08-27 16:37             ` Petr Tesarik
2010-08-27 16:08 ` Luck, Tony
2010-08-27 16:08   ` Luck, Tony
2010-08-27 17:16   ` Petr Tesarik
2010-08-27 17:16     ` Petr Tesarik
2010-08-27 18:20     ` Hedi Berriche
2010-08-27 18:20       ` Hedi Berriche
2010-08-27 19:40     ` Petr Tesarik
2010-08-27 19:40       ` Petr Tesarik
2010-08-27 20:29   ` Luck, Tony
2010-08-27 20:29     ` Luck, Tony
2010-08-27 20:41     ` Petr Tesarik [this message]
2010-08-27 20:41       ` Petr Tesarik
2010-08-27 21:03     ` Petr Tesarik
2010-08-27 21:03       ` Petr Tesarik
2010-08-27 21:11       ` Luck, Tony
2010-08-27 21:11         ` Luck, Tony
2010-08-27 22:13         ` Petr Tesarik
2010-08-27 22:13           ` Petr Tesarik
2010-08-27 23:26           ` Luck, Tony
2010-08-27 23:26             ` Luck, Tony
2010-08-27 23:55             ` Luck, Tony
2010-08-27 23:55               ` Luck, Tony
2010-08-28  0:28               ` Hedi Berriche
2010-08-28  0:28                 ` Hedi Berriche
2010-08-28  5:01                 ` Luck, Tony
2010-08-28  5:01                   ` Luck, Tony
2010-08-30 18:17                   ` Luck, Tony
2010-08-30 18:17                     ` Luck, Tony
2010-08-30 21:41                     ` Petr Tesarik
2010-08-30 21:41                       ` Petr Tesarik
2010-08-30 22:43                       ` Tony Luck
2010-08-30 22:43                         ` Tony Luck
2010-08-31 22:17                         ` Tony Luck
2010-08-31 22:17                           ` Tony Luck
2010-09-01 23:09                           ` Tony Luck
2010-09-01 23:09                             ` Tony Luck
2010-09-02  0:26                             ` Hedi Berriche
2010-09-02  0:26                               ` Hedi Berriche
2010-09-03  0:06                               ` Tony Luck
2010-09-03  0:06                                 ` Tony Luck
2010-09-03  9:04                                 ` Petr Tesarik
2010-09-03  9:04                                   ` Petr Tesarik
2010-09-03 14:35                                   ` Petr Tesarik
2010-09-03 14:35                                     ` Petr Tesarik
2010-09-03 14:52                                     ` Petr Tesarik
2010-09-03 14:52                                       ` Petr Tesarik
2010-09-03 15:50                                       ` Tony Luck
2010-09-03 15:50                                         ` Tony Luck
2010-09-06 14:47                                         ` Petr Tesarik
2010-09-06 14:47                                           ` Petr Tesarik
2010-09-07 13:17                                           ` Petr Tesarik
2010-09-07 13:17                                             ` Petr Tesarik
2010-09-07 17:35                                             ` Tony Luck
2010-09-07 17:35                                               ` Tony Luck
2010-09-08 15:55                                               ` Tony Luck
2010-09-08 15:55                                                 ` Tony Luck
2010-09-10  2:55                                     ` Dave Jones
2010-09-10  2:55                                       ` Dave Jones

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