From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:46730) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZDVfl-0006gF-Rl for qemu-devel@nongnu.org; Fri, 10 Jul 2015 06:36:50 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZDVfk-0001kW-Gy for qemu-devel@nongnu.org; Fri, 10 Jul 2015 06:36:49 -0400 Date: Fri, 10 Jul 2015 12:36:40 +0200 (CEST) From: Alexandre DERUMIER Message-ID: <534630199.9583032.1436524600797.JavaMail.zimbra@oxygem.tv> In-Reply-To: <20150710071333.GA16297@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> <278695903.9362838.1436511286250.JavaMail.zimbra@oxygem.tv> <20150710071333.GA16297@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 >>Does it completely hang?=20 yes, can't ping network, and vnc console is frozen. >>What does "perf top" show?=20 I'll do test today . (I'm going to vacation this night,I'll try to send res= ults before that) ----- Mail original ----- De: "Fam Zheng" =C3=80: "aderumier" Cc: "Stefan Hajnoczi" , "Kevin Wolf" = , "qemu-devel" , qemu-block@nongnu.org Envoy=C3=A9: Vendredi 10 Juillet 2015 09:13:33 Objet: Re: [Qemu-devel] [Qemu-block] [PATCH 0/3] mirror: Fix guest responsi= veness during bitmap scan On Fri, 07/10 08:54, Alexandre DERUMIER wrote:=20 > >>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=20 >=20 > With 1ms sleep, I can reproduce the hang 100% with a fast cpu (xeon e5 v3= 3,1ghz) and source raw file on nfs.=20 Does it completely hang? I can't reproduce this with my machine mirroring f= rom=20 nfs to local: the guest runs smoothly. What does "perf top" show?=20 Fam=20 >=20 >=20 > ----- Mail original -----=20 > De: "Fam Zheng" =20 > =C3=80: "Stefan Hajnoczi" =20 > Cc: "Kevin Wolf" , "qemu-devel" = , qemu-block@nongnu.org=20 > Envoy=C3=A9: Vendredi 10 Juillet 2015 08:43:50=20 > Objet: Re: [Qemu-devel] [Qemu-block] [PATCH 0/3] mirror: Fix guest respon= siveness during bitmap scan=20 >=20 > 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 >=20 > That's because they all can be perfectly mitigated by setting a reasonabl= e=20 > "speed" that matchs the host horsepower. Thinking about this again, I dou= bt=20 > that lengthening the duration with a hardcoded value benifits everyone; a= nd=20 > before Alexandre's reply on old server/slow disks, I don't recall any rep= ort,=20 > because the coroutines would already yield often enough, when waiting for= IO to=20 > complete. So I am not sure whether they're broken in practice.=20 >=20 > Fam=20