Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761010AbXH0Tjo (ORCPT ); Mon, 27 Aug 2007 15:39:44 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757919AbXH0Tjh (ORCPT ); Mon, 27 Aug 2007 15:39:37 -0400 Received: from netops-testserver-3-out.sgi.com ([192.48.171.28]:34564 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1756455AbXH0Tjh (ORCPT ); Mon, 27 Aug 2007 15:39:37 -0400 Date: Mon, 27 Aug 2007 12:39:35 -0700 (PDT) From: Christoph Lameter X-X-Sender: clameter@schroedinger.engr.sgi.com To: Peter Zijlstra cc: Mathieu Desnoyers , akpm@linux-foundation.org, linux-kernel@vger.kernel.org, mingo@redhat.com Subject: Re: [PATCH] SLUB use cmpxchg_local In-Reply-To: <1188197539.6114.426.camel@twins> Message-ID: References: <20070820201519.512791382@polymtl.ca> <20070820201822.597720007@polymtl.ca> <20070820204126.GA22507@Krystal> <20070820212922.GA27011@Krystal> <20070820215413.GA28452@Krystal> <20070821173849.GA8360@Krystal> <1188197539.6114.426.camel@twins> 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: 716 Lines: 15 On Mon, 27 Aug 2007, Peter Zijlstra wrote: > So, if the fast path can be done with a preempt off, it might be doable > to suffer the slow path with a per cpu lock like that. Sadly the cmpxchg_local requires local per cpu data access. Isnt there some way to make this less expensive on RT? Acessing cpu local memory is really good for performance on NUMA since the data is optimally placed and one can avoid/reduce locking if the process stays tied to the processor. - 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/