From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:36397) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bS1dt-0002uq-BT for qemu-devel@nongnu.org; Tue, 26 Jul 2016 08:39:26 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bS1dp-00082p-C9 for qemu-devel@nongnu.org; Tue, 26 Jul 2016 08:39:25 -0400 Received: from smtp3.mundo-r.com ([212.51.32.191]:42887 helo=smtp4.mundo-r.com) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bS1dp-0007tM-4h for qemu-devel@nongnu.org; Tue, 26 Jul 2016 08:39:21 -0400 Date: Tue, 26 Jul 2016 14:38:43 +0200 From: Alberto Garcia Message-ID: <20160726123843.GA10992@igalia.com> References: <20160714121819.GR15476@stefanha-x1.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160714121819.GR15476@stefanha-x1.localdomain> Subject: Re: [Qemu-devel] Confusing I/O throttling behavior with burst_length > 1 and max < avg List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Stefan Hajnoczi Cc: qemu-devel@nongnu.org, ngu@redhat.com On Thu, Jul 14, 2016 at 01:18:19PM +0100, Stefan Hajnoczi wrote: > The following throttling behavior was observed with bps=512000 > bps_max=51200 throttling.bps-total-max-length=2: > > READ: io=512KB, aggrb=50KB/s, minb=50KB/s, maxb=50KB/s, mint=10061msec, maxt=10061msec > > If bps-total-max-length=1 then the result is different: > > READ: io=5056KB, aggrb=505KB/s, minb=505KB/s, maxb=505KB/s, mint=10006msec, maxt=10006msec > > The burst limits guest bps instead of adding on top of it when > burst_length > 1. Thanks Stefan, I think we should forbid that kind of setup altogether. I wrote a few more details in the bug report: > https://bugzilla.redhat.com/show_bug.cgi?id=1355665 I can write the patch. Berto