From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hedi Berriche Date: Fri, 27 Aug 2010 13:48:02 +0000 Subject: Re: Serious problem with ticket spinlocks on ia64 Message-Id: <20100827134802.GX18967@zorg.emea.sgi.com> List-Id: References: <201008271537.35709.ptesarik@suse.cz> In-Reply-To: <201008271537.35709.ptesarik@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Petr Tesarik Cc: linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org, Tony Luck 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 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 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753568Ab0H0Nsp (ORCPT ); Fri, 27 Aug 2010 09:48:45 -0400 Received: from relay2.sgi.com ([192.48.179.30]:59080 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753371Ab0H0Nsn (ORCPT ); Fri, 27 Aug 2010 09:48:43 -0400 Date: Fri, 27 Aug 2010 14:48:02 +0100 From: Hedi Berriche To: Petr Tesarik Cc: linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org, Tony Luck Subject: Re: Serious problem with ticket spinlocks on ia64 Message-ID: <20100827134802.GX18967@zorg.emea.sgi.com> Mail-Followup-To: Petr Tesarik , linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org, Tony Luck References: <201008271537.35709.ptesarik@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <201008271537.35709.ptesarik@suse.cz> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 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