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b=dkBUZNknJoaodqbygE+wDDgb+Fcazkw0c74vKOd8bDYqktR4j/Imib/aDRomKDYZi +fNV7mgBoRHpdwFjQl2/J2ExV383W678NdHczJHGfwoTyncfRpUsvuF51BiKMN8u3V 5inCcoRbgnZDzEkuf+geQDo6T9d6PEP6aj4FAlNo= X-UI-Sender-Class: c548c8c5-30a9-4db5-a2e7-cb6cb037b8f9 Received: from luklap ([88.130.61.42]) by smtp.web.de (mrweb101 [213.165.67.124]) with ESMTPSA (Nemesis) id 0Lrs70-1klyo03Kyk-013gSS; Fri, 31 Jul 2020 09:52:26 +0200 Date: Fri, 31 Jul 2020 09:52:17 +0200 From: Lukas Straub To: Derek Su Subject: Re: [PATCH v1 0/1] COLO: migrate dirty ram pages before colo checkpoint Message-ID: <20200731094940.7a26e583@luklap> In-Reply-To: <20200621021004.5559-1-dereksu@qnap.com> References: <20200621021004.5559-1-dereksu@qnap.com> MIME-Version: 1.0 Content-Type: multipart/signed; boundary="Sig_/J.VP9aqn2UTKOSVy+4jyF49"; protocol="application/pgp-signature"; micalg=pgp-sha512 X-Provags-ID: V03:K1:vqEl0azvZ94Vtj3JXkqoT/YSqoiirLLTapXvmNjEW4SFJP1kF6T iMo8E4igeEBpJTPLSpzgfBycpuoT9CsvZWQa7N7v8FGewxTzj+MegDKZD+/gIfIRS7maH1B CBPUlGs6PMM9lzPrDsIzWYwl3oaxYkEbtGoEK7VqVfh31hR6KrT/M/gnMrAES6h3Zi3AQbq cKN6UG2JycAGMU+z4Vs5g== X-UI-Out-Filterresults: notjunk:1;V03:K0:Oj56s0PUhM8=:AL9D597BdW/PPyXUv7jOfU pBJhFPUTl6sNcWEz/eQQIqf4CjYU+ull2ij2SHxkW/HL+6QIzYpNf4oYrpHqcPpa5ZlEn+RLF JH3i84oXIFJ0jv0ZsaE5/IPlfSVWu0aGBTdoiEHC/eiksebCmXADVkSHIPJupWNhMGCaSJQCJ f+d1hdfLTR3wsMnxzg6wVrcqzWY7HUdgeqhuR7jpCh9VmUJ/+nZS3AC8eSfJE7onQjUnOKXPL xRflHDg0rm8pv7BJN4wmX/Ofqv7dXWNzu7q5LlxdlTPeZLzutdfgejIEh33YmYzMa8HasSN7v rnnr6TyMfKJTTBmb9siBQWPdP1J+ikF5exynyBmkrjRc0nffDjbQTlkaJs2cfUl+Lly38TGYM k1FEYMONZSSrvDaVNGkl9CqVPDE9y5dMpUyYfHSAOduf0Z5sHF3pVrxqfIHPNBH3prkRPq0m4 xBv4ox/6fAaEK5YSNIOuC3MdvxLoPISYgItGenoO2Rww19HQQSgNNF7rwLUM+3r8cvaiVNfGT czbZ9pupcLowIZAUE0y24Hr6rKqDumiJH4bBXRPLpcdN6cSsPNs1+wI614LA076VPZfIoMcM5 D0ziFMPsn/lUPPzw8Gsui3tbORBE0AfQI/MnQeSUR2g0ZzKBeDlvQWeiFOM+er0xMHO0u0KiI CIJsPZtMZfC5pQfeW845fktBligzvTx4kB4lbSNE6pIAwPsrcJGOJG0nSq2PYWoNWoDHrQdMb jg8rPIXTUKE0Ge2B6ViuI3ZXAaHlzGiHLKIt2JwqJJWb7q7bQ0VTicdGXeaW8z74eAmiT0Bnq YDCS1uIAxnJO8XfWo3yv1Jss7RlL6ZxEnN+ymeiFu9ZsJ1nwA4MKj6Tyk2aHhUigcEZ0SbB2b 86QM0bf0GYOQ9UImsswcHqC7diEOEtV3IOlyAas5azkwFPiaTZlcbyXJspC2CUVtxgcDtXI6h keireGARMwa1/rMJbMJt7V2MmKxWGa62jVq4TA8e7nxnT/rzrjySzhgo2sRnIV+CW1FKC4D7U IsSP7VkrJKcwxllaHwHJgPZNT79NDk0NN2fJbF+oHAhd6POvgwzKOrI2vodnzA6s/H/cSk32x ktgIMCswVT1uDFvJq5HHRZKEF1tOI/hkym35tNmWu50SlD2HF3M/sN1/8aBzEuBHhFHL7pcWR jSzv/woW4ujj0CKRl2cSyTDJnalsIMyAKG4lBzyMMgDmyWTN+h8YE248bkeiwGPWRzNBUuFQ5 iBUNWTWWR+9FOESEWdEUnuA+awSduEzV/q40ShQ== Received-SPF: pass client-ip=217.72.192.78; envelope-from=lukasstraub2@web.de; helo=mout.web.de X-detected-operating-system: by eggs.gnu.org: First seen = 2020/07/31 03:52:36 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] X-Spam_score_int: -34 X-Spam_score: -3.5 X-Spam_bar: --- X-Spam_report: (-3.5 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, FREEMAIL_ENVFROM_END_DIGIT=0.25, FREEMAIL_FROM=0.001, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H2=-1, 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: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: zhang.zhanghailiang@huawei.com, chyang@qnap.com, quintela@redhat.com, qemu-devel@nongnu.org, dgilbert@redhat.com, ctcheng@qnap.com, jwsu1986@gmail.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" --Sig_/J.VP9aqn2UTKOSVy+4jyF49 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable On Sun, 21 Jun 2020 10:10:03 +0800 Derek Su wrote: > This series is to reduce the guest's downtime during colo checkpoint > by migrating dirty ram pages as many as possible before colo checkpoint. >=20 > If the iteration count reaches COLO_RAM_MIGRATE_ITERATION_MAX or > ram pending size is lower than 'x-colo-migrate-ram-threshold', > stop the ram migration and do colo checkpoint. >=20 > Test environment: > The both primary VM and secondary VM has 1GiB ram and 10GbE NIC > for FT traffic. > One fio buffer write job runs on the guest. = = =20 > The result shows the total primary VM downtime is decreased by ~40%. >=20 > Please help to review it and suggestions are welcomed. > Thanks. Hello Derek, Sorry for the late reply. I think this is not a good idea, because it unnecessarily introduces a dela= y between checkpoint request and the checkpoint itself and thus impairs net= work bound workloads due to increased network latency. Workloads that are i= ndependent from network don't cause many checkpoints anyway, so it doesn't = help there either. Hailang did have a patch to migrate ram between checkpoints, which should h= elp all workloads, but it wasn't merged back then. I think you can pick it = up again, rebase and address David's and Eric's comments: https://lore.kernel.org/qemu-devel/20200217012049.22988-3-zhang.zhanghailia= ng@huawei.com/T/#u Hailang, are you ok with that? 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