From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:33796) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dIhSv-00041x-IL for qemu-devel@nongnu.org; Wed, 07 Jun 2017 16:22:07 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dIhSr-0007qa-J0 for qemu-devel@nongnu.org; Wed, 07 Jun 2017 16:22:05 -0400 Received: from out1-smtp.messagingengine.com ([66.111.4.25]:57087) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dIhSr-0007qM-Ed for qemu-devel@nongnu.org; Wed, 07 Jun 2017 16:22:01 -0400 Date: Wed, 7 Jun 2017 16:22:00 -0400 From: "Emilio G. Cota" Message-ID: <20170607202200.GA20593@flamenco> References: <20170605165233.4135-1-rth@twiddle.net> <20170605165233.4135-23-rth@twiddle.net> <87h8zrdh02.fsf@linaro.org> <87fufbdghz.fsf@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <87fufbdghz.fsf@linaro.org> Subject: Re: [Qemu-devel] [PULL 22/26] target/aarch64: optimize indirect branches List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Alex =?iso-8859-1?Q?Benn=E9e?= Cc: Richard Henderson , qemu-devel@nongnu.org, peter.maydell@linaro.org On Wed, Jun 07, 2017 at 15:22:48 +0100, Alex Bennée wrote: > > Alex Bennée writes: > > > Richard Henderson writes: > > > >> From: "Emilio G. Cota" > >> > >> Measurements: > >> > >> [Baseline performance is that before applying this and the previous > >> commit] > > > > Sadly this has regressed my qemu-system-aarch64 EL2 run. It was slightly > > masked by an unrelated assertion breakage which I had to fix. However > > with this patch my boot hangs spinning all 4 threads. Once reverted > > things work again. > > > > My command line: > > > > timeout -k 1s --foreground 120s ./aarch64-softmmu/qemu-system-aarch64 -machine type=virt -display none -m 4096 -cpu cortex-a57 -serial mon:stdio -netdev user,id=unet -device virtio-net-device,netdev=unet -drive file=/home/alex/lsrc/qemu/images/jessie-arm64.qcow2,id=myblock,index=0,if=none -device virtio-blk-device,drive=myblock -append "console=ttyAMA0 root=/dev/vda1 systemd.unit=benchmark.service" -kernel /home/alex/lsrc/qemu/images/aarch64-current-linux-kernel-only.img -smp 4 -machine gic-version=3 -machine virtualization=true -name debug-threads=on > > > > My tree with fix and revert: > > > > https://github.com/stsquad/qemu/tree/debug/aarch64-hang > > > > I'm investigating now. > > Well this seems to be a case of hangs with -smp > 1 (which I guess was > obvious seeing as the TCG threads seem to be spinning against each > other). Not sure the problem is in MTTCG; I cannot reproduce with -smp > 1 and thread=single; can you? [ I get no output whatsoever when trying to boot ] Note that you'll need to revert bde4d9205ee to get thread=foo to work again -- see [1]. Thanks, E. [1] https://lists.gnu.org/archive/html/qemu-devel/2017-06/msg01980.html