From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:36801) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1borSE-0005br-HP for qemu-devel@nongnu.org; Tue, 27 Sep 2016 08:25:47 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1borS8-0001XY-Ae for qemu-devel@nongnu.org; Tue, 27 Sep 2016 08:25:45 -0400 Received: from [202.114.0.240] (port=17891 helo=mail.hust.edu.cn) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1borS7-0001W1-48 for qemu-devel@nongnu.org; Tue, 27 Sep 2016 08:25:40 -0400 Date: Tue, 27 Sep 2016 20:28:49 +0800 (GMT+08:00) From: "Chunguang Li" Message-ID: <1cd703e.8bb8.1576b9e743a.Coremail.lichunguang@hust.edu.cn> In-Reply-To: <20160926185235.GJ2029@work-vm> References: <5feb15.7e53.1576070ae2d.Coremail.lichunguang@hust.edu.cn> <20160926112349.GF2029@work-vm> <13289d.86da.15766fdf27c.Coremail.lichunguang@hust.edu.cn> <20160926185235.GJ2029@work-vm> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] Migration dirty bitmap: should only mark pages as dirty after they have been sent List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Dr. David Alan Gilbert" Cc: qemu-devel@nongnu.org, amit.shah@redhat.com, pbonzini@redhat.com, stefanha@redhat.com, quintela@redhat.com > -----=E5=8E=9F=E5=A7=8B=E9=82=AE=E4=BB=B6----- > =E5=8F=91=E4=BB=B6=E4=BA=BA: "Dr. David Alan Gilbert" > =E5=8F=91=E9=80=81=E6=97=B6=E9=97=B4: 2016=E5=B9=B49=E6=9C=8827=E6=97=A5 = =E6=98=9F=E6=9C=9F=E4=BA=8C > =E6=94=B6=E4=BB=B6=E4=BA=BA: "Chunguang Li" > =E6=8A=84=E9=80=81: qemu-devel@nongnu.org, amit.shah@redhat.com, pbonzini= @redhat.com, stefanha@redhat.com, quintela@redhat.com > =E4=B8=BB=E9=A2=98: Re: [Qemu-devel] Migration dirty bitmap: should only = mark pages as dirty after they have been sent >=20 > Yes, it's probably pretty bad; and we really need to do something like > split the sync into smaller chunks; there are other suggestions > for how to improve it (e.g. there's the page-modification-logging > changes). >=20 > However, I don't think you usually get really random writes, if you > do precopy rarely converges at all, because even without your > observation it changes lots and lots of pages. >=20 > Dave >=20 > -- > Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK I have read a little about the page-modification-logging. I think=20 it is only a more efficient way for dirty logging with better performance,= =20 compared with write protection, but will not solve the problem we are talking about. The only idea to handle this, which I have come up with so far,=20 is to split the sync into smaller chunks that you have mentioned. Maybe I can start from this idea to try to fix it. If you come up with some other idea or suggestion, please let me know. Thank you~ Chunguang -- Chunguang Li, Ph.D. Candidate Wuhan National Laboratory for Optoelectronics (WNLO) Huazhong University of Science & Technology (HUST) Wuhan, Hubei Prov., China