From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 5952 invoked by alias); 17 Jul 2011 16:55:13 -0000 Received: (qmail 5933 invoked by uid 22791); 17 Jul 2011 16:55:11 -0000 X-SWARE-Spam-Status: No, hits=-1.6 required=5.0 tests=AWL,BAYES_00,DKIM_SIGNED,DKIM_VALID,TW_CX,TW_GC,TW_GX,TW_IB X-Spam-Check-By: sourceware.org Received: from ud10.udmedia.de (HELO mail.ud10.udmedia.de) (194.117.254.50) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Sun, 17 Jul 2011 16:54:54 +0000 Received: (qmail 11527 invoked from network); 17 Jul 2011 18:54:51 +0200 Received: from unknown (HELO x4.trippels.de) (ud10?360p3@91.64.57.18) by mail.ud10.udmedia.de with ESMTPSA (DHE-RSA-AES256-SHA encrypted, authenticated); 17 Jul 2011 18:54:51 +0200 Date: Sun, 17 Jul 2011 17:55:00 -0000 From: Markus Trippelsdorf To: Richard Guenther Cc: Eric Botcazou , gcc-patches@gcc.gnu.org, Ian Lance Taylor , Diego Novillo , gcc@gcc.gnu.org Subject: Re: PATCH RFA: Build stages 2 and 3 with C++ Message-ID: <20110717165451.GA14418@x4.trippels.de> References: <201107171330.55167.ebotcazou@adacore.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: 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: 2011-07/txt/msg00289.txt.bz2 On 2011.07.17 at 18:30 +0200, Richard Guenther wrote: > On Sun, Jul 17, 2011 at 1:30 PM, Eric Botcazou wrote: > >> I have measured it at some point and IIRC it was about 10% slower > >> (comparing C bootstrap with C++ in stag1 languages with C++ bootstrap, > >> not sure if that included bootstrapping libstdc++ for the former). > > > > IMO acceptable now that the build time of libjava has been halved. > > Actually the penalty for using C++ was only 1.5%, that of bootstrapping C++ and > libstdc++ was 15%. For reference: I've tested the difference today on an average 4 CPU machine with 8GB RAM. This is the result of otherwise identical LTO+PGO builds: --enable-build-with-cxx make -j4 profiledbootstrap 3384.20s user 177.02s system 291% cpu 20:23.12 total make -j4 profiledbootstrap 3011.03s user 144.30s system 297% cpu 17:41.59 total That's a ~15% increase in build time. (I couldn't test --enable-build-poststage1-with-cxx, because it doesn't seem to work with this configuration. Maybe the patch needs to be updated to also cover LTO or PGO builds?) Configured with: ../gcc/configure --prefix=/usr --bindir=/usr/x86_64-pc-linux-gnu/gcc-bin/4.7.0 --includedir=/usr/lib/gcc/x86_64-pc-linux-gnu/4.7.0/include --datadir=/usr/share/gcc-data/x86_64-pc-linux-gnu/4.7.0 --mandir=/usr/share/gcc-data/x86_64-pc-linux-gnu/4.7.0/man --infodir=/usr/share/gcc-data/x86_64-pc-linux-gnu/4.7.0/info --with-gxx-include-dir=/usr/lib/gcc/x86_64-pc-linux-gnu/4.7.0/include/g++-v4 --host=x86_64-pc-linux-gnu --build=x86_64-pc-linux-gnu --disable-altivec --disable-fixed-point --without-ppl --without-cloog --enable-lto --enable-nls --without-included-gettext --with-system-zlib --disable-werror --with-gold --enable-secureplt --disable-multilib --enable-libmudflap --disable-libssp --enable-libgomp --enable-cld --with-python-dir=/share/gcc-data/x86_64-pc-linux-gnu/4.7.0/python --enable-checking=release --disable-libgcj --enable-languages=c,c++ --enable-shared --enable-threads=posix --enable-__cxa_atexit --enable-clocale=gnu --with-build-config=bootstrap-lto And built with: make -j4 BOOT_CFLAGS="-march=native -O2 -pipe" STAGE1_CFLAGS="-march=native -O2 -pipe" CFLAGS_FOR_TARGET="-march=native -O2 -pipe" profiledbootstrap -- Markus