Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753786Ab0BRKZ5 (ORCPT ); Thu, 18 Feb 2010 05:25:57 -0500 Received: from casper.infradead.org ([85.118.1.10]:57435 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750717Ab0BRKZz (ORCPT ); Thu, 18 Feb 2010 05:25:55 -0500 Subject: Re: [PATCH 09/10] x86-32: use SSE for atomic64_read/set if available From: Peter Zijlstra To: Luca Barbieri Cc: Andi Kleen , mingo@elte.hu, hpa@zytor.com, akpm@linux-foundation.org, linux-kernel@vger.kernel.org In-Reply-To: References: <1266406962-17463-1-git-send-email-luca@luca-barbieri.com> <1266406962-17463-10-git-send-email-luca@luca-barbieri.com> <87eikj54wp.fsf@basil.nowhere.org> Content-Type: text/plain; charset="UTF-8" Date: Thu, 18 Feb 2010 11:24:49 +0100 Message-ID: <1266488689.26719.114.camel@laptop> Mime-Version: 1.0 X-Mailer: Evolution 2.28.2 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 804 Lines: 20 On Thu, 2010-02-18 at 10:53 +0100, Luca Barbieri wrote: > perf is currently the main user. > On Core2, lock cmpxchg8b takes about 24 cycles and writes the > cacheline, while movlps takes 1 cycle. Then run a 64bit kernel already, then its a simple 1 cycle read. The only platform this might possibly be worth the effort for it Atom, the rest of the world has moved on to 64bit a long time ago. There might still be a few pentium-m users out there that might appreciate this too, but still.. That said, _iff_ this can be done nicely there's no objection. -- 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/