Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760012AbXESDuz (ORCPT ); Fri, 18 May 2007 23:50:55 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754766AbXESDus (ORCPT ); Fri, 18 May 2007 23:50:48 -0400 Received: from srv5.dvmed.net ([207.36.208.214]:53624 "EHLO mail.dvmed.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750893AbXESDus (ORCPT ); Fri, 18 May 2007 23:50:48 -0400 Message-ID: <464E7409.6020505@garzik.org> Date: Fri, 18 May 2007 23:50:33 -0400 From: Jeff Garzik User-Agent: Thunderbird 1.5.0.10 (X11/20070302) MIME-Version: 1.0 To: Nick Piggin CC: Andrew Morton , Phillip Susi , Alex Volkov , "'Linux Kernel Mailing List'" Subject: Re: aio is unlikely References: <20070509151831.f5956b66.akpm@linux-foundation.org> <058f01c7998e$1406e370$650df7cd@MUMBA> <20070518140624.1a4db517.akpm@linux-foundation.org> <464E2098.8020900@cfl.rr.com> <20070518151259.319e09da.akpm@linux-foundation.org> <464E2AA6.3080402@garzik.org> <464E7254.60406@yahoo.com.au> In-Reply-To: <464E7254.60406@yahoo.com.au> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Spam-Score: -4.3 (----) X-Spam-Report: SpamAssassin version 3.1.8 on srv5.dvmed.net summary: Content analysis details: (-4.3 points, 5.0 required) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 743 Lines: 19 Nick Piggin wrote: > Aside from using branch constructs or hints that help the predictor > guess the right way... I think gcc will move unlikely paths right past > the end of the "likely" fastpath, so it can increase code size and be > somewhat suboptimal in terms of icache usage. Thanks for the reminder. GCC definitely does code movement. ISTR the code movement might even be "extreme", once the unit-at-a-time support arrived, placing "cold" code at the end of the compiled module. Jeff - 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/