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Lunev" , Eric Blake , Markus Armbruster Subject: Re: [PATCH 8/9] block/accounting: Move latency_ns override down Message-ID: <20260921204237.GD115897@fedora> References: <20260831135206.126184-1-hreitz@redhat.com> <20260831135206.126184-9-hreitz@redhat.com> <20260903150842.GF825275@fedora> <292ff2f9-b3fe-423b-9b36-ada26904a617@redhat.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="ZjcocTV0L2RXAo+Z" Content-Disposition: inline In-Reply-To: <292ff2f9-b3fe-423b-9b36-ada26904a617@redhat.com> X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.93 Received-SPF: pass client-ip=170.10.129.124; envelope-from=stefanha@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: 12 X-Spam_score: 1.2 X-Spam_bar: + X-Spam_report: (1.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, 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_H2=0.001, RCVD_IN_SBL_CSS=3.335, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: qemu development 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 --ZjcocTV0L2RXAo+Z Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Wed, Sep 16, 2026 at 10:21:22AM +0200, Hanna Czenczek wrote: > On 03.09.26 17:08, Stefan Hajnoczi wrote: > > On Mon, Aug 31, 2026 at 03:52:04PM +0200, Hanna Czenczek wrote: > > > I am not quite sure why `latency_ns` is overridden by a fixed value in > > > qtest mode because personally, I find it much better if I can > > > individually change requests' latency by modifying the qtest clock. > > It looks like tests/qemu-iotests/136 relies on a hardcoded constant so > > it can check min/max/avg against known values. > >=20 > > > But I'm not going to change existing behavior for the histogram and > > > such, so I will just move this override after the latency has been > > > evaluated regarding a potential BLOCK_IO_DELAY event. > > That's fine if you aren't taking the same testing approach as > > tests/qemu-iotests/136. I think the benefit of hardcoding the value for > > testing is that it would become possible to trigger the latency > > threshold without worrying about timing in the test environment. >=20 > FWIW, as far as I understand, in qtest mode, `clock_type` is > `QEMU_CLOCK_VIRTUAL`, so it is not dependent on the test environment anyw= ay, > but on the qtest clock. That=E2=80=99s why I don=E2=80=99t understand the= fixed latency > value, but maybe it was just easier this way for 136 because this way it > does not have to do a clock_step for each request. Yes, I think you're right. I'm not sure either. :/ Stefan --ZjcocTV0L2RXAo+Z Content-Type: application/pgp-signature; name=signature.asc -----BEGIN PGP SIGNATURE----- iQEzBAEBCgAdFiEEhpWov9P5fNqsNXdanKSrs4Grc8gFAmqxlr0ACgkQnKSrs4Gr c8g0Lgf/aoIbkW0m+MQVWEUbM1/6427JnvUGkLMdeEsG0LYTGgn5JrykDeMBLyUM eH1C44gAiBHBI5Namd0/5R8UyWepeND4RY99QYDw9gIxTbwy/9r2ULi8NRaOZHCi 5oMz2cqjO1a/yXSm0Je1h7b9kT9R7UpKTeppRimBG7HVT93tIYliMF1Kqfm85Xgw v+NhbQJPHs1dQbaZHY5sPOMwC1TQSs8cMaMA9xMxvU//FJoWPJ0xE/qyRXnxz7aX gTjg4DYk6iJH/x78uyOm3mNzlqFh/WxpSGg8oNrFP1SlG1SE2gUENcWrXRwSaNcu C338p3BBUBlp80gPvCfNLHOMxdSSAA== =88Dp -----END PGP SIGNATURE----- --ZjcocTV0L2RXAo+Z--