From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 5006 invoked by alias); 19 Mar 2010 16:27:45 -0000 Received: (qmail 4993 invoked by uid 22791); 19 Mar 2010 16:27:44 -0000 X-SWARE-Spam-Status: No, hits=-2.3 required=5.0 tests=AWL,BAYES_00 X-Spam-Check-By: sourceware.org Received: from smtp.ispras.ru (HELO smtp.ispras.ru) (83.149.198.201) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Fri, 19 Mar 2010 16:27:40 +0000 Received: from ispserv.ispras.ru (ispserv.ispras.ru [83.149.198.72]) by smtp.ispras.ru (Postfix) with ESMTP id 52DA05D40D7; Fri, 19 Mar 2010 19:27:30 +0300 (MSK) Received: from monoid.intra.ispras.ru (winnie.ispras.ru [83.149.198.236]) by ispserv.ispras.ru (Postfix) with ESMTP id 37D5B3FC48; Fri, 19 Mar 2010 19:27:37 +0300 (MSK) Date: Fri, 19 Mar 2010 16:34:00 -0000 From: Alexander Monakov To: Ian Bolton cc: gcc@gcc.gnu.org Subject: Re: Understanding Scheduling In-Reply-To: <4D60B0700D1DB54A8C0C6E9BE69163700E08F38E@EXCHANGEVS.IceraSemi.local> Message-ID: References: <4D60B0700D1DB54A8C0C6E9BE69163700E08F38E@EXCHANGEVS.IceraSemi.local> User-Agent: Alpine 2.00 (LNX 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Mailing-List: contact gcc-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Archive: List-Post: List-Help: Sender: gcc-owner@gcc.gnu.org X-SW-Source: 2010-03/txt/msg00298.txt.bz2 On Fri, 19 Mar 2010, Ian Bolton wrote: > Let's start with sched1 ... > > For our architecture at least, it seems like Richard Earnshaw is > right that sched1 is generally bad when you are using -Os, because > it can increase register pressure and cause extra spill/fill code when > you move independent instructions in between dependent instructions. Please note that Vladimir Makarov implemented register pressure-aware sched1 for GCC 4.5, activated with -fsched-pressure. I thought I should mention this because your e-mail omits it completely, so it's hard to tell whether you tested it. Best regards, Alexander Monakov