From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:57748) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Snmxv-00074T-DQ for qemu-devel@nongnu.org; Sun, 08 Jul 2012 04:35:40 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Snmxt-0004mJ-DI for qemu-devel@nongnu.org; Sun, 08 Jul 2012 04:35:38 -0400 Received: from mailout2.samsung.com ([203.254.224.25]:34992) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Snmxt-0004iy-2o for qemu-devel@nongnu.org; Sun, 08 Jul 2012 04:35:37 -0400 Received: from epcpsbgm2.samsung.com (mailout2.samsung.com [203.254.224.25]) by mailout2.samsung.com (Oracle Communications Messaging Server 7u4-24.01(7.0.4.24.0) 64bit (built Nov 17 2011)) with ESMTP id <0M6U00IE72J63KA0@mailout2.samsung.com> for qemu-devel@nongnu.org; Sun, 08 Jul 2012 17:35:30 +0900 (KST) Received: from [172.21.111.108] ([182.198.1.3]) by mmp2.samsung.com (Oracle Communications Messaging Server 7u4-24.01 (7.0.4.24.0) 64bit (built Nov 17 2011)) with ESMTPA id <0M6U00K6A2J58J90@mmp2.samsung.com> for qemu-devel@nongnu.org; Sun, 08 Jul 2012 17:35:30 +0900 (KST) Date: Sun, 08 Jul 2012 17:35:36 +0900 From: Yeongkyoon Lee In-reply-to: Message-id: <4FF94658.40000@samsung.com> MIME-version: 1.0 Content-type: text/plain; charset=UTF-8; format=flowed Content-transfer-encoding: QUOTED-PRINTABLE References: <1341494619-4714-1-git-send-email-yeongkyoon.lee@samsung.com> <1341494619-4714-5-git-send-email-yeongkyoon.lee@samsung.com> <4FF6CF4A.7070200@samsung.com> Subject: Re: [Qemu-devel] [RFC][PATCH v2 4/4] configure: add CONFIG_QEMU_LDST_OPTIMIZATION for TCG qemu_ld/st optimization List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Blue Swirl Cc: laurent.desnogues@gmail.com, Peter Maydell , e.voevodin@samsung.com, qemu-devel@nongnu.org, chenwj@iis.sinica.edu.tw On 2012=EB=85=84 07=EC=9B=94 07=EC=9D=BC 16:51, Blue Swirl wrote: > On Fri, Jul 6, 2012 at 11:43 AM, Yeongkyoon Lee > wrote: >> On 2012=EB=85=84 07=EC=9B=94 05=EC=9D=BC 23:06, Peter Maydell wrot= e: >>> On 5 July 2012 14:23, Yeongkyoon Lee = wrote: >>>> Add an option "--enable-ldst-optimization" to enable >>>> CONFIG_QEMU_LDST_OPTIMIZATION macro for TCG qemu_ld/st optimizat= ion. It only >>>> works with CONFIG_SOFTMMU and doesn't work with CONFIG_TCG_PASS_= AREG0. >>> This shouldn't be a user settable config option -- we should >>> just identify what the optimal setting is for the guest/target >>> combination and use it. >> >> It looks better remove the option after it is confirmed that it wo= rks well >> for all the guest target architectures. >> >> >>>> case "$target_arch2" in >>>> alpha | sparc* | xtensa* | ppc*) >>>> echo "CONFIG_TCG_PASS_AREG0=3Dy" >> $config_target_mak >>>> + # qemu_ld/st optimization is not available with >>>> CONFIG_TCG_PASS_AREG0 >>>> + target_ldst_optimization=3D"no" >>> PASS_AREG0 is the way of the future -- you need to fix the ldst >>> optimization to work with it. >> >> There are two reasons to prevent working with PASS_AREG0. >> The first one is I'm not sure the history and future PASS_AREG0 an= d have not >> tested PASS_AREG0 which is only enabled for some guest architectur= es.. >> The second is a problem of too many conditional paths in sources. >> I think it is not late to combine the ldst optimization with PASS_= AREG0 >> after the ldst optimization agreed as default. > It looks like you already support PASS_AREG0, the slow path code ju= st > passes AREG0 as the first call argument. > > The code in slow path is currently dead code just for future PASS_ARE= G0=20 porting. It needs some porting for actual working.