From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:44427) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1f6Esd-0006ya-Fx for qemu-devel@nongnu.org; Wed, 11 Apr 2018 08:29:41 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1f6Esa-00052k-BY for qemu-devel@nongnu.org; Wed, 11 Apr 2018 08:29:39 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:51464 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1f6Esa-000529-7m for qemu-devel@nongnu.org; Wed, 11 Apr 2018 08:29:36 -0400 Date: Wed, 11 Apr 2018 13:29:24 +0100 From: "Dr. David Alan Gilbert" Message-ID: <20180411122923.GE2667@work-vm> References: <1523089594-1422-1-git-send-email-lidongchen@tencent.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1523089594-1422-1-git-send-email-lidongchen@tencent.com> Subject: Re: [Qemu-devel] [PATCH 0/5] Enable postcopy RDMA live migration List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Lidong Chen Cc: quintela@redhat.com, qemu-devel@nongnu.org, adido@mellanox.com, licq@mellanox.com, Lidong Chen * Lidong Chen (jemmy858585@gmail.com) wrote: > Current Qemu RDMA communication does not support send and receive > data at the same time, so when RDMA live migration with postcopy > enabled, the source qemu return path thread get qemu file error. > > Those patch add the postcopy support for RDMA live migration. This description is a little misleading; it doesn't really do RDMA during the postcopy phase - what it really does is disable the RDMA page sending during the postcopy phase, relying on the RDMA codes stream emulation to send the page. That's not necessarily a bad fix; you get the nice performance of RDMA during the precopy phase, but how bad are you finding the performance during the postcopy phase - the RDMA code we have was only really designed for sending small commands over the stream? Dave > Lidong Chen (5): > migration: create a dedicated connection for rdma return path > migration: add the interface to set get_return_path > migration: implement the get_return_path for RDMA iochannel > migration: fix qemu carsh when RDMA live migration > migration: disable RDMA WRITR after postcopy started. > > migration/qemu-file-channel.c | 12 ++-- > migration/qemu-file.c | 13 +++- > migration/qemu-file.h | 2 +- > migration/rdma.c | 148 ++++++++++++++++++++++++++++++++++++++++-- > 4 files changed, 163 insertions(+), 12 deletions(-) > > -- > 1.8.3.1 > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK