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Tsirkin" To: Michael Galaxy Cc: Sean Hefty , Peter Xu , "Gonglei (Arei)" , "qemu-devel@nongnu.org" , "yu.zhang@ionos.com" , "elmar.gerdes@ionos.com" , zhengchuan , "berrange@redhat.com" , "armbru@redhat.com" , "lizhijian@fujitsu.com" , "pbonzini@redhat.com" , Xiexiangyou , "linux-rdma@vger.kernel.org" , "lixiao (H)" , "jinpu.wang@ionos.com" , Wangjialin Subject: Re: [PATCH 0/6] refactor RDMA live migration based on rsocket API Message-ID: <20240929141323-mutt-send-email-mst@kernel.org> References: <1717503252-51884-1-git-send-email-arei.gonglei@huawei.com> <20240827165643-mutt-send-email-mst@kernel.org> <027c4f24-f515-4fdb-8770-6bf2433e0f43@akamai.com> <84c74f1a95a648b18c9d41b8c5ef2f60@huawei.com> <0730fa9b-49cd-46e4-9264-afabe2486154@akamai.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <0730fa9b-49cd-46e4-9264-afabe2486154@akamai.com> Received-SPF: pass client-ip=170.10.129.124; envelope-from=mst@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -21 X-Spam_score: -2.2 X-Spam_bar: -- X-Spam_report: (-2.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.095, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_CERTIFIED_BLOCKED=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Sat, Sep 28, 2024 at 12:52:08PM -0500, Michael Galaxy wrote: > A bounce buffer defeats the entire purpose of using RDMA in these cases. > When using RDMA for very large transfers like this, the goal here is to map > the entire memory region at once and avoid all CPU interactions (except for > message management within libibverbs) so that the NIC is doing all of the > work. > > I'm sure rsocket has its place with much smaller transfer sizes, but this is > very different. To clarify, are you actively using rdma based migration in production? Stepping up to help maintain it? -- MST