From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S265928AbUBKRbe (ORCPT ); Wed, 11 Feb 2004 12:31:34 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S265966AbUBKRbd (ORCPT ); Wed, 11 Feb 2004 12:31:33 -0500 Received: from ns.suse.de ([195.135.220.2]:3535 "EHLO Cantor.suse.de") by vger.kernel.org with ESMTP id S265928AbUBKRbc (ORCPT ); Wed, 11 Feb 2004 12:31:32 -0500 Date: Sat, 14 Feb 2004 20:43:26 +0100 From: Andi Kleen To: Andi Kleen Cc: ap@swapped.cc, linux-kernel@vger.kernel.org Subject: Re: [PATCH] [2.6] [2/2] hlist: remove IFs from hlist functions Message-Id: <20040214204326.4d9fc423.ak@suse.de> In-Reply-To: <20040214195949.2ad9aa4f.ak@suse.de> References: <4029CB7E.4030003@swapped.cc.suse.lists.linux.kernel> <4029CF24.1070307@osdl.org.suse.lists.linux.kernel> <4029D2D5.7070504@swapped.cc.suse.lists.linux.kernel> <402A5CEC.2030603@swapped.cc> <20040214195949.2ad9aa4f.ak@suse.de> X-Mailer: Sylpheed version 0.9.7 (GTK+ 1.2.10; i686-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 14 Feb 2004 19:59:49 +0100 Andi Kleen wrote: > > A full cache miss is extremly costly on a modern Gigahertz+ CPU because > memory and busses are far slower than the CPU core. As a rule of > thumb 1000+ cycles. An CMP is extremly cheap (a few cycles at worst), > the only thing that could be more expensive is an mispredicted conditional > jump triggered by the CMP. But even that would be at best a few tens of cycles. > If everything is mispredicted which should be common it's extremly fast ^^^^^^^^^^^^^ predicted of course -Andi