From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 26137 invoked by alias); 13 May 2009 10:12:41 -0000 Received: (qmail 26002 invoked by uid 22791); 13 May 2009 10:12:40 -0000 X-SWARE-Spam-Status: No, hits=-2.7 required=5.0 tests=AWL,BAYES_00,RCVD_IN_DNSWL_LOW,RCVD_IN_SORBS_WEB,SPF_HELO_PASS,SPF_PASS X-Spam-Check-By: sourceware.org Received: from main.gmane.org (HELO ciao.gmane.org) (80.91.229.2) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Wed, 13 May 2009 10:12:34 +0000 Received: from list by ciao.gmane.org with local (Exim 4.43) id 1M4BRw-0000DY-Ak for gcc@gcc.gnu.org; Wed, 13 May 2009 10:12:32 +0000 Received: from 93-34-222-182.ip51.fastwebnet.it ([93.34.222.182]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Wed, 13 May 2009 10:12:32 +0000 Received: from bonzini by 93-34-222-182.ip51.fastwebnet.it with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Wed, 13 May 2009 10:12:32 +0000 To: gcc@gcc.gnu.org From: Paolo Bonzini Subject: Re: New GCC releases comparison and comparison of GCC4.4 and LLVM2.5 on SPEC2000 Date: Wed, 13 May 2009 11:35:00 -0000 Message-ID: <4A0A9D0C.4070503@gnu.org> References: <4A098018.1030900@redhat.com> <87d4admp8f.fsf@basil.nowhere.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: "Joseph S. Myers" , Chris Lattner , Vladimir Makarov , "gcc.gcc.gnu.org" , Evan Cheng User-Agent: Thunderbird 2.0.0.21 (Macintosh/20090302) In-Reply-To: <87d4admp8f.fsf@basil.nowhere.org> X-IsSubscribed: yes 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: 2009-05/txt/msg00336.txt.bz2 Message-ID: <20090513113500.XjGbFoT9d_qcfLgq0WmI6RrM6ma7R-k94qVaXU0LC9w@z> Andi Kleen wrote: > "Joseph S. Myers" writes: > >> On Tue, 12 May 2009, Chris Lattner wrote: >> >>> 1. I have a hard time understanding the code size numbers. Does 10% mean that >>> GCC is generating 10% bigger or 10% smaller code than llvm? >> I have a different comment on the code size numbers: could we have >> comparisons of code size for -Os rather than (or in addition to) -O2 and >> -O3? If someone is particularly concerned with code size, -Os is what >> they are expected to use. > > It's a slippery slope that -O2 is getting so bad regarding > code size. What should people do who need performance, but cannot > completely disregard code size (and can't use profile feedback for > some reason). >From looking http://vmakarov.fedorapeople.org/spec/I2Size32.png it does not look that bad at all. For SpecFP it is different, but code size is rarely a problem in FP benchmarks (hot loops are really small or really huge anyway). So it looks like we're doing the right thing in that respect. Rather, we should seriously understand what caused the compilation time jump in 4.2, and whether those are still a problem. We made a good job in 4.0 and 4.3 offsetting the slowdowns from infrastructure changes with speedups from other changes; and 4.4 while slower than 4.3 at least stays below 4.2. But, 4.2 was a disaster for compilation time. Paolo