From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Dr. David Alan Gilbert" Subject: Re: [PATCH 1/8] migration: stop compressing page in migration thread Date: Mon, 19 Mar 2018 12:11:47 +0000 Message-ID: <20180319121147.GC3206@work-vm> References: <20180313075739.11194-1-xiaoguangrong@tencent.com> <20180313075739.11194-2-xiaoguangrong@tencent.com> <20180315102501.GA3062@work-vm> <423c901d-16b6-67fb-262b-3021e30871ec@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: liang.z.li@intel.com, kvm@vger.kernel.org, quintela@redhat.com, mtosatti@redhat.com, Xiao Guangrong , qemu-devel@nongnu.org, mst@redhat.com, pbonzini@redhat.com To: Xiao Guangrong Return-path: Content-Disposition: inline In-Reply-To: <423c901d-16b6-67fb-262b-3021e30871ec@gmail.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+gceq-qemu-devel2=m.gmane.org@nongnu.org Sender: "Qemu-devel" List-Id: kvm.vger.kernel.org * Xiao Guangrong (guangrong.xiao@gmail.com) wrote: > > Hi David, > > Thanks for your review. > > On 03/15/2018 06:25 PM, Dr. David Alan Gilbert wrote: > > > > migration/ram.c | 32 ++++++++++++++++---------------- > > > > Hi, > > Do you have some performance numbers to show this helps? Were those > > taken on a normal system or were they taken with one of the compression > > accelerators (which I think the compression migration was designed for)? > > Yes, i have tested it on my desktop, i7-4790 + 16G, by locally live migrate > the VM which has 8 vCPUs + 6G memory and the max-bandwidth is limited to 350. > > During the migration, a workload which has 8 threads repeatedly written total > 6G memory in the VM. Before this patchset, its bandwidth is ~25 mbps, after > applying, the bandwidth is ~50 mbps. OK, that's good - worth adding those notes to your cover letter. I wonder how well it works with compression acceleration hardware; I can't see anything in this series making it worse. > BTW, Compression will use almost all valid bandwidth after all of our work > which i will post it out part by part. Oh, that will be very nice. Dave -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK