From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1NxvSz-0000qF-Bg for qemu-devel@nongnu.org; Sat, 03 Apr 2010 01:00:17 -0400 Received: from [140.186.70.92] (port=33284 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1NxvSx-0000q7-3I for qemu-devel@nongnu.org; Sat, 03 Apr 2010 01:00:16 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.69) (envelope-from ) id 1NxvSr-0002Pr-IY for qemu-devel@nongnu.org; Sat, 03 Apr 2010 01:00:14 -0400 Received: from static-71-162-243-5.phlapa.fios.verizon.net ([71.162.243.5]:58366 helo=grelber.thyrsus.com) by eggs.gnu.org with esmtp (Exim 4.69) (envelope-from ) id 1NxvSr-0002HG-AO for qemu-devel@nongnu.org; Sat, 03 Apr 2010 01:00:09 -0400 From: Rob Landley Subject: Re: [Qemu-devel] Significant performance regression in qemu-system-mips. Date: Fri, 2 Apr 2010 23:58:08 -0500 References: <201003241534.01219.rob@landley.net> <20100401213309.GA19428@hall.aurel32.net> In-Reply-To: <20100401213309.GA19428@hall.aurel32.net> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-15" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <201004022358.09604.rob@landley.net> List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Aurelien Jarno Cc: qemu-devel@nongnu.org On Thursday 01 April 2010 16:33:09 Aurelien Jarno wrote: > On Wed, Mar 24, 2010 at 03:34:00PM -0500, Rob Landley wrote: > > Reverting that patch fixed it (git show HEAD | patch -R -p1), by which I > > mean three consecutive runs with 30 second timeout didn't trigger the > > hang detection. > > I have tried to reproduce the issue by measuring the boot time of a mips > system, but it stay unchanged between before and after the patch. Do you > have some more details about how to reproduce the issue ? Have you tried > to pay with the -clock option? It was fixed by commit ca5a2a4b12bd447 from Paolo Bonzini, which is in current -git. (I just confirmed that current -git builds fine.) If you did want to reproduce the issue get and extract http://impactlinux.com/fwl/downloads/firmware-0.9.11.tar.bz2 Create a mips system image: ./build.sh mips And when the noise dies down run the native build with: sources/native-builds/static-tools.sh temp.hdc sources/more/native-build.sh mips temp.hdc output 30 That creates a build control image (temp.hdc, with the source tarballs for dropbear and strace and a control script to build static binaries of both), and then runs a native build using the mips system image under qemu (it'll grab qemu-system-mips from your $PATH), uploading the results into the "output" directory on the host, with a 30 second inactivity timeout. When the bug was manifesting, it usually wouldn't even complete with a 60 second timeout, let alone 30. (Paolo said disabling dynticks would help, but his patch seems to have fixed it properly.) Thanks, Rob -- Latency is more important than throughput. It's that simple. - Linus Torvalds