From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:36003) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Z76Iv-00061g-Kt for qemu-devel@nongnu.org; Mon, 22 Jun 2015 14:18:46 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Z76Iq-0002lO-FP for qemu-devel@nongnu.org; Mon, 22 Jun 2015 14:18:45 -0400 Received: from greensocs.com ([193.104.36.180]:35455) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Z76Iq-0002kB-6l for qemu-devel@nongnu.org; Mon, 22 Jun 2015 14:18:40 -0400 Message-ID: <5588517C.9000909@greensocs.com> Date: Mon, 22 Jun 2015 20:18:36 +0200 From: Frederic Konrad MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: [Qemu-devel] 4 CPUs with vexpress is slow? List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel Cc: Peter Maydell , =?ISO-8859-1?Q?Alex_Benn=E9?= =?ISO-8859-1?Q?e?= Hi, Testing MTTCG patch-set performance I found strange slowness with _upstream_ qemu (46bca5404b08201bb9df1ac32bc88fc7e6db1f74). Basically booting a vexpress-a15 with "-smp 4" takes approximately forever if I use a vexpress-v2p-ca15-tc1.dtb (2x A15) dtb and 39 secs if I hack this dtb to have 4 CPUs. This is definitely strange because if I use "-smp 2" with the same guest image it takes only 4 secs. And MTTCG patch-set seems to fix the issue as it boot in 6 secs with "-smp 4". Is that a known issue or maybe it's my guest (linux 3.13.5)? Fred