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([2804:431:c7ed:cb75:d392:178:9101:5763]) by smtp.gmail.com with ESMTPSA id r132-20020a37a88a000000b006af373cec2csm17010803qke.70.2022.07.04.11.13.10 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 04 Jul 2022 11:13:12 -0700 (PDT) Message-ID: <97f75348557212d32bb38c20b6800208219e4aa8.camel@redhat.com> Subject: Re: [PATCH v2 2/3] Add zero-copy-copied migration stat From: Leonardo =?ISO-8859-1?Q?Br=E1s?= To: "Daniel P." =?ISO-8859-1?Q?Berrang=E9?= , Markus Armbruster , "Dr. David Alan Gilbert" Cc: Juan Quintela , Eric Blake , Peter Xu , qemu-devel@nongnu.org Date: Mon, 04 Jul 2022 15:13:08 -0300 In-Reply-To: References: <20220701155935.482503-1-leobras@redhat.com> <20220701155935.482503-3-leobras@redhat.com> <877d4tz9gx.fsf@pond.sub.org> <87k08tw0bq.fsf@pond.sub.org> <87czelvxrt.fsf@pond.sub.org> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.44.2 MIME-Version: 1.0 Received-SPF: pass client-ip=170.10.133.124; envelope-from=leobras@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=-0.082, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, 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" Thanks Daniel, Markus and Dave for the feedback! On Mon, 2022-07-04 at 14:14 +0100, Daniel P. Berrang=C3=A9 wrote: > On Mon, Jul 04, 2022 at 02:59:50PM +0200, Markus Armbruster wrote: > > Daniel P. Berrang=C3=A9 writes: > >=20 > > > On Mon, Jul 04, 2022 at 02:04:41PM +0200, Markus Armbruster wrote: > >=20 [...] >=20 > since 7.1, unless you're planning for really tortuous review :) >=20 Ok, updated :) > > [...] > >=20 > > > > Please rephrase the documentation of @zero-copy-copied in terms of > > > > @dirty-sync-count.=C2=A0 Here's my attempt. > > > >=20 > > > > # @zero-copy-copied: Number of times dirty RAM synchronization coul= d not > > > > #=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 avoid copying zero pages.= =C2=A0 This is between 0 and > > > > #=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 @dirty-sync-count.=C2=A0 (= since 7.1) That's a great description! And it's almost 100% correct. IIUC dirty-sync-count increments on migration_bitmap_sync() once after each= full dirty-bitmap scan, and even with multifd syncing at the same point, it coul= d potentially have a increment per multifd channel. The only change would be having: # This is between 0 and @dirty-sync-count * @multifd-channel. > > >=20 > > > Any one have preferences on the name - i get slight put off by the > > > repeated word in the property name here. > > >=20 > > > =C2=A0=C2=A0 @zero-copy-rejects ? > > > =C2=A0=C2=A0 @zero-copy-misses ? > > > =C2=A0=C2=A0 @zero-copy-fails ? > >=20 > > I'd consider any of these an improvement.=C2=A0 Not a native speaker, b= ut > > perhaps "failures" instead of "fails". > >=20 > > We could also express the connection to @dirty-sync-count right in the > > name, like @dirty-sync-rejected-zero-copy, @dirty-sync-missed-zero-copy= , > > @dirty-sync-failed-zero-copy.=C2=A0 Or maybe -copies. >=20 > Yeah, @dirty-sync-missed-zero-copy=C2=A0=C2=A0 is probably my favourite. Ok then, this one there is :) I will update my patchset with the suggestions, and I should publish a v3 shortly.=20 Best regards, Leo >=20 > With regards, > Daniel