From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:54787) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZDSCz-0008PN-3P for qemu-devel@nongnu.org; Fri, 10 Jul 2015 02:54:53 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZDSCx-0000eQ-UT for qemu-devel@nongnu.org; Fri, 10 Jul 2015 02:54:53 -0400 Date: Fri, 10 Jul 2015 08:54:46 +0200 (CEST) From: Alexandre DERUMIER Message-ID: <278695903.9362838.1436511286250.JavaMail.zimbra@oxygem.tv> In-Reply-To: <20150710064350.GG31230@ad.nay.redhat.com> References: <1436413678-7114-1-git-send-email-famz@redhat.com> <20150709130208.GD11166@stefanha-thinkpad.redhat.com> <20150710064350.GG31230@ad.nay.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [Qemu-block] [PATCH 0/3] mirror: Fix guest responsiveness during bitmap scan List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Fam Zheng Cc: Kevin Wolf , Stefan Hajnoczi , qemu-devel , qemu-block@nongnu.org >>Thinking about this again, I doubt >>that lengthening the duration with a hardcoded value benifits everyone; a= nd >>before Alexandre's reply on old server/slow disks With 1ms sleep, I can reproduce the hang 100% with a fast cpu (xeon e5 v3 3= ,1ghz) and source raw file on nfs. ----- Mail original ----- De: "Fam Zheng" =C3=80: "Stefan Hajnoczi" Cc: "Kevin Wolf" , "qemu-devel" , = qemu-block@nongnu.org Envoy=C3=A9: Vendredi 10 Juillet 2015 08:43:50 Objet: Re: [Qemu-devel] [Qemu-block] [PATCH 0/3] mirror: Fix guest responsi= veness during bitmap scan On Thu, 07/09 14:02, Stefan Hajnoczi wrote:=20 > This patch only converts the mirror block job to use the new relax=20 > function. The other block jobs (stream, backup, commit) are still using= =20 > a 0 ns delay and are therefore broken. They should probably be=20 > converted in the same series.=20 That's because they all can be perfectly mitigated by setting a reasonable= =20 "speed" that matchs the host horsepower. Thinking about this again, I doubt= =20 that lengthening the duration with a hardcoded value benifits everyone; and= =20 before Alexandre's reply on old server/slow disks, I don't recall any repor= t,=20 because the coroutines would already yield often enough, when waiting for I= O to=20 complete. So I am not sure whether they're broken in practice.=20 Fam=20