From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:60194) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZSowh-0004ys-UM for qemu-devel@nongnu.org; Fri, 21 Aug 2015 12:13:36 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZSowg-00068D-Mt for qemu-devel@nongnu.org; Fri, 21 Aug 2015 12:13:35 -0400 Received: from hall.aurel32.net ([2001:bc8:30d7:100::1]:34689) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZSowg-00066i-Hl for qemu-devel@nongnu.org; Fri, 21 Aug 2015 12:13:34 -0400 Date: Fri, 21 Aug 2015 18:13:22 +0200 From: Aurelien Jarno Message-ID: <20150821161322.GA13757@aurel32.net> References: <55D37189.3010809@twiddle.net> <20150819110010.GJ23508@aurel32.net> <55D60C1B.9010502@twiddle.net> <55D6A9DF.5070506@gmx.net> <55D6BC00.50200@twiddle.net> <55D6BFAD.4080501@gmx.net> <55D74828.6050209@twiddle.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <55D74828.6050209@twiddle.net> Subject: Re: [Qemu-devel] Debian 7.8.0 SPARC64 on qemu - anything i can do to speedup the emulation? List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Richard Henderson Cc: Artyom Tarasenko , Dennis Luehring , qemu-devel On 2015-08-21 08:47, Richard Henderson wrote: > On 08/20/2015 11:05 PM, Dennis Luehring wrote: > >> > g++ src/pugixml.cpp -g -Wall -Wextra -Werror -pedantic -std=c++0x -c -MMD -MP > >> > > >> > tcg-indirect: ~2:46.5 > >> > qemu.org-git: ~2:51.2 (worst result) > >> > without-optimization: ~2:14.1 (best result) > >> > >> No compiler optimization? I wouldn't expect there to be much for tcg to > >> optimize there -- dropping values to memory all the time doesn't leave much. > > > > > > without-optimization means qemu.org-git release build + undefine > > USE_TCG_OPTIMIZATIONS in tcg/tcg.c > > or what compiler do you mean? > > The one for compiling the benchmark: g++ -O2. > > >> These results are weird. Unoptimized less than half the speed of mainline? > >> Improving optimization (with no extra work, mind) brings the results back down? > > > > > > yep they are - it seems that the assumption of the involved developers > > where speed can be improved / or slowbess comes from is not correct > > how are SPARC64 benchmarks done usually? > > *shrug* No different than any other... It would be interesting to know if the time taking to generate code is actually used for code translation or code re-translation. The way the MMU is modelled might triggered plenty of costly retranslation. This happens for example on SH4, and to a lesser extent on MIPS. Aurelien -- Aurelien Jarno GPG: 4096R/1DDD8C9B aurelien@aurel32.net http://www.aurel32.net