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Mon, 04 Mar 2024 05:17:30 -0800 (PST) X-Google-Smtp-Source: AGHT+IHGCweczouJUnnw2M9NwAAYPI0IK0Sng9hVeXDzfcrUnDOXanVXx9oKNTesnXoY+jfQsnePUQ== X-Received: by 2002:a17:90a:db81:b0:299:c3d:c00e with SMTP id h1-20020a17090adb8100b002990c3dc00emr7191079pjv.3.1709558250352; Mon, 04 Mar 2024 05:17:30 -0800 (PST) Received: from x1n ([43.228.180.230]) by smtp.gmail.com with ESMTPSA id gb2-20020a17090b060200b0029acce2420asm7688077pjb.10.2024.03.04.05.17.28 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 04 Mar 2024 05:17:30 -0800 (PST) Date: Mon, 4 Mar 2024 21:17:21 +0800 From: Peter Xu To: Fabiano Rosas Cc: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= , qemu-devel@nongnu.org, armbru@redhat.com, Claudio Fontana Subject: Re: [PATCH v6 00/23] migration: File based migration with multifd and mapped-ram Message-ID: References: <20240229153017.2221-1-farosas@suse.de> <87bk7unny2.fsf@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <87bk7unny2.fsf@suse.de> Received-SPF: pass client-ip=170.10.133.124; envelope-from=peterx@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -26 X-Spam_score: -2.7 X-Spam_bar: -- X-Spam_report: (-2.7 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.571, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 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 Mon, Mar 04, 2024 at 10:09:25AM -0300, Fabiano Rosas wrote: > Perhaps if we move the fsync to the same spot as the multifd thread sync > instead of having a big one at the end? Not sure how that looks with > concurrency in the mix. Can try, but I think the bottleneck should normally be on the block backend, in which case I won't be surprised concurrency on flushing won't help then. Please see my other proposal on removing fdatasync() from qemu; I could overlook some reason to have it, though.. -- Peter Xu