Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754423AbZCQTft (ORCPT ); Tue, 17 Mar 2009 15:35:49 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753096AbZCQTfk (ORCPT ); Tue, 17 Mar 2009 15:35:40 -0400 Received: from tomts40.bellnexxia.net ([209.226.175.97]:54870 "EHLO tomts40-srv.bellnexxia.net" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752924AbZCQTfj (ORCPT ); Tue, 17 Mar 2009 15:35:39 -0400 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: As0FABuTv0lMQW1W/2dsb2JhbACBTtMag3wG Date: Tue, 17 Mar 2009 15:35:32 -0400 From: Mathieu Desnoyers To: David Miller Cc: ltt-dev@lists.casi.polymtl.ca, mingo@elte.hu, paulmck@linux.vnet.ibm.com, jwboyer@linux.vnet.ibm.com, linux-kernel@vger.kernel.org Subject: Re: cli/sti vs local_cmpxchg and local_add_return Message-ID: <20090317193532.GA18503@Krystal> References: <20090317013220.GA22474@Krystal> <20090317050135.GB6859@linux.vnet.ibm.com> <20090317160635.GE10092@Krystal> <20090317.122816.246078801.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline In-Reply-To: <20090317.122816.246078801.davem@davemloft.net> X-Editor: vi X-Info: http://krystal.dyndns.org:8080 X-Operating-System: Linux/2.6.21.3-grsec (i686) X-Uptime: 15:31:57 up 17 days, 15:58, 1 user, load average: 0.27, 0.43, 0.46 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 Content-Length: 1114 Lines: 31 * David Miller (davem@davemloft.net) wrote: > From: Mathieu Desnoyers > Date: Tue, 17 Mar 2009 12:06:35 -0400 > > > But powerpc has non-maskable interrupts, so for less than 4 cycles, I > > think it's better to stay with the local_t variant to be NMI-safe. > > Sparc64 has non-maskable interrupts too btw. > OK, this alone is a strong argument to favor NMI-safe lockless algorithm even if it is a bit slower. We should see what kind of performance impact it has on overall tracing performance to find out if it will make a measurable difference anyway. Mathieu > _______________________________________________ > ltt-dev mailing list > ltt-dev@lists.casi.polymtl.ca > http://lists.casi.polymtl.ca/cgi-bin/mailman/listinfo/ltt-dev > -- Mathieu Desnoyers OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/