From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:41351) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TdHbV-00019q-QD for qemu-devel@nongnu.org; Tue, 27 Nov 2012 04:37:22 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1TdHbP-00079p-SB for qemu-devel@nongnu.org; Tue, 27 Nov 2012 04:37:21 -0500 Received: from mx1.redhat.com ([209.132.183.28]:14071) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TdHbP-00079h-KM for qemu-devel@nongnu.org; Tue, 27 Nov 2012 04:37:15 -0500 Message-ID: <50B489C7.7080608@redhat.com> Date: Tue, 27 Nov 2012 10:37:11 +0100 From: Paolo Bonzini MIME-Version: 1.0 References: <1354005361-17805-1-git-send-email-pbonzini@redhat.com> <50B48790.8030705@linux.vnet.ibm.com> In-Reply-To: <50B48790.8030705@linux.vnet.ibm.com> Content-Type: text/plain; charset=GB2312 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH 1.3] build: compile translate.o at -O1 optimization List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Wenchao Xia Cc: qemu-devel@nongnu.org Il 27/11/2012 10:27, Wenchao Xia ha scritto: > In tcg case I think translate.o will influent performance obviously, > how about adding an option "fast-build" to use -O1 for it by default. > If you agree I will adding that after this patch upstream which fix > build bot failure quickly. This is not about having a fast or slow build, it's about not requiring a ludicrous amount of memory... Besides, translate.c is usually not too high in the profiles. Most of the time is spent _executing_ JIT-translated code, not translating it. Note that there is probably one or two GCC options that can be fine-tuned to avoid the explosion instead of just -O1 vs. -O2. If you have an affected machine (F18) you can help by compiling translate.c with -O2 -ftime-report. I planned to do this today, but I first need to install a F18 virtual machine. Paolo