Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760664AbXH0WaN (ORCPT ); Mon, 27 Aug 2007 18:30:13 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753687AbXH0WaA (ORCPT ); Mon, 27 Aug 2007 18:30:00 -0400 Received: from netops-testserver-3-out.sgi.com ([192.48.171.28]:48348 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753016AbXH0W36 (ORCPT ); Mon, 27 Aug 2007 18:29:58 -0400 Date: Mon, 27 Aug 2007 15:29:57 -0700 (PDT) From: Christoph Lameter X-X-Sender: clameter@schroedinger.engr.sgi.com To: Mathieu Desnoyers cc: Peter Zijlstra , akpm@linux-foundation.org, linux-kernel@vger.kernel.org, mingo@redhat.com Subject: Re: [PATCH] SLUB use cmpxchg_local In-Reply-To: <20070827222715.GA16982@Krystal> Message-ID: References: <1188197539.6114.426.camel@twins> <20070827202203.GB5653@Krystal> <20070827203913.GA7416@Krystal> <20070827211003.GA10627@Krystal> <20070827213845.GB9748@Krystal> <20070827222715.GA16982@Krystal> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 955 Lines: 19 On Mon, 27 Aug 2007, Mathieu Desnoyers wrote: > Hrm, I just want to certify one thing: A lot of code paths seems to go > to the slow path without requiring cmpxchg_local to execute at all. So > is the slow path more likely to be triggered by the (!object), > (!node_match) tests or by these same tests done in the redo after the > initial cmpxchg_local ? The slow path is more likely to be triggered by settings in the per cpu structure. The cmpxchg failure is comparatively rare. So the worst case is getting worse but the average use of interrupt enable/disable may not change much. Need to have some measurements to confirm that. I can try to run the emulation on IA64 and see what the result will be. - 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/