From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:48632) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dIbqu-0000Qr-QG for qemu-devel@nongnu.org; Wed, 07 Jun 2017 10:22:29 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dIbqq-0000DB-W1 for qemu-devel@nongnu.org; Wed, 07 Jun 2017 10:22:28 -0400 Received: from mail-wm0-x234.google.com ([2a00:1450:400c:c09::234]:37745) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1dIbqq-0000D4-Nv for qemu-devel@nongnu.org; Wed, 07 Jun 2017 10:22:24 -0400 Received: by mail-wm0-x234.google.com with SMTP id d73so12373640wma.0 for ; Wed, 07 Jun 2017 07:22:24 -0700 (PDT) References: <20170605165233.4135-1-rth@twiddle.net> <20170605165233.4135-23-rth@twiddle.net> <87h8zrdh02.fsf@linaro.org> From: Alex =?utf-8?Q?Benn=C3=A9e?= In-reply-to: <87h8zrdh02.fsf@linaro.org> Date: Wed, 07 Jun 2017 15:22:48 +0100 Message-ID: <87fufbdghz.fsf@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit 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: Richard Henderson Cc: qemu-devel@nongnu.org, peter.maydell@linaro.org, "Emilio G. Cota" 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). -- Alex Bennée