From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754014AbZHPKb2 (ORCPT ); Sun, 16 Aug 2009 06:31:28 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752248AbZHPKb1 (ORCPT ); Sun, 16 Aug 2009 06:31:27 -0400 Received: from cantor2.suse.de ([195.135.220.15]:39946 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751939AbZHPKb1 (ORCPT ); Sun, 16 Aug 2009 06:31:27 -0400 Date: Sun, 16 Aug 2009 12:31:27 +0200 From: Nick Piggin To: Manfred Spraul Cc: Andrew Morton , Nadia Derbey , Pierre Peiffer , linux-kernel@vger.kernel.org Subject: Re: [PATCH] [patch 4a/4] ipc: sem optimise simple operations Message-ID: <20090816103127.GB8644@wotan.suse.de> References: <200908141946.n7EJkh7B018160@mail.q-ag.de> <20090815045237.GC19195@wotan.suse.de> <4A86899A.6050502@colorfullife.com> <20090815103820.GC8954@wotan.suse.de> <4A86ABF0.2070207@colorfullife.com> <20090815144908.GA30951@wotan.suse.de> <4A86E30E.8030208@colorfullife.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4A86E30E.8030208@colorfullife.com> User-Agent: Mutt/1.5.9i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Aug 15, 2009 at 06:32:14PM +0200, Manfred Spraul wrote: > It depends. After disabling inlining, including all helper functions > that differ: > > My proposal: 301 bytes for update_queue. > > "simple", only negv: 226 bytes > "simple, negv+zero: 354 bytes > simple+complex: 526 bytes. > > Thus with only +-1 simple ops, your version uses less icache. If both > +-1 and 0 ops are used, your version uses more icache. Don't forget that in that case, your version is badly suboptimal due to the algorithmic complexity.