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[188.85.150.151]) by smtp.gmail.com with ESMTPSA id m10-20020a7bce0a000000b00405953973c3sm3886456wmc.6.2023.10.05.07.36.11 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 05 Oct 2023 07:36:11 -0700 (PDT) From: Juan Quintela To: Vladimir Sementsov-Ogievskiy Cc: Thomas Huth , Peter Maydell , Kevin Wolf , hreitz@redhat.com, qemu-devel@nongnu.org, Daniel Berrange , richard.henderson@linaro.org, Qemu-block Subject: Re: How to tame CI? In-Reply-To: <602039f4-2a22-49ed-ab19-5ca62c9f2b47@yandex-team.ru> (Vladimir Sementsov-Ogievskiy's message of "Thu, 5 Oct 2023 15:35:15 +0300") References: <87fs5aho6e.fsf@secure.mitica> <602039f4-2a22-49ed-ab19-5ca62c9f2b47@yandex-team.ru> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.3 (gnu/linux) Date: Thu, 05 Oct 2023 16:36:10 +0200 Message-ID: <87ttr5jfvp.fsf@secure.mitica> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Received-SPF: pass client-ip=170.10.133.124; envelope-from=quintela@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 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_H3=0.001, RCVD_IN_MSPIKE_WL=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: , Reply-To: quintela@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Vladimir Sementsov-Ogievskiy wrote: > On 26.07.23 16:32, Thomas Huth wrote: >> On 26/07/2023 15.00, Peter Maydell wrote: >>> On Wed, 26 Jul 2023 at 13:06, Juan Quintela wrote: >>>> To make things easier, this is the part that show how it breaks (this = is >>>> the gcov test): >>>> >>>> 357/423 qemu:block / io-qcow2-copy-before-write=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=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 ERROR=C2= =A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 6.38s=C2=A0=C2=A0= exit status 1 >>>>>>> PYTHON=3D/builds/juan.quintela/qemu/build/pyvenv/bin/python3 >>>> MALLOC_PERTURB_=3D44 >>>> /builds/juan.quintela/qemu/build/pyvenv/bin/python3 >>>> /builds/juan.quintela/qemu/build/../tests/qemu-iotests/check -tap >>>> -qcow2 copy-before-write --source-dir >>>> /builds/juan.quintela/qemu/tests/qemu-iotests --build-dir >>>> /builds/juan.quintela/qemu/build/tests/qemu-iotests >>>> =E2=80=95=E2=80=95=E2=80=95=E2=80=95=E2=80=95=E2=80=95=E2=80=95=E2=80= =95=E2=80=95=E2=80=95=E2=80=95=E2=80=95=E2=80=95=E2=80=95=E2=80=95=E2=80=95= =E2=80=95=E2=80=95=E2=80=95=E2=80=95=E2=80=95=E2=80=95=E2=80=95=E2=80=95=E2= =80=95=E2=80=95=E2=80=95=E2=80=95=E2=80=95=E2=80=95=E2=80=95=E2=80=95=E2=80= =95=E2=80=95=E2=80=95=E2=80=95=E2=80=95 =E2=9C=80=C2=A0 =E2=80=95=E2=80=95= =E2=80=95=E2=80=95=E2=80=95=E2=80=95=E2=80=95=E2=80=95=E2=80=95=E2=80=95=E2= =80=95=E2=80=95=E2=80=95=E2=80=95=E2=80=95=E2=80=95=E2=80=95=E2=80=95=E2=80= =95=E2=80=95=E2=80=95=E2=80=95=E2=80=95=E2=80=95=E2=80=95=E2=80=95=E2=80=95= =E2=80=95=E2=80=95=E2=80=95=E2=80=95=E2=80=95=E2=80=95=E2=80=95=E2=80=95=E2= =80=95=E2=80=95 >>>> stderr: >>>> --- /builds/juan.quintela/qemu/tests/qemu-iotests/tests/copy-before-wr= ite.out >>>> +++ /builds/juan.quintela/qemu/build/scratch/qcow2-file-copy-before-wr= ite/copy-before-write.out.bad >>>> @@ -1,5 +1,21 @@ >>>> -.... >>>> +...F >>>> +=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D >>>> +FAIL: test_timeout_break_snapshot (__main__.TestCbwError) >>>> +---------------------------------------------------------------------- >>>> +Traceback (most recent call last): >>>> +=C2=A0 File "/builds/juan.quintela/qemu/tests/qemu-iotests/tests/copy= -before-write", line 210, in test_timeout_break_snapshot >>>> +=C2=A0=C2=A0=C2=A0 self.assertEqual(log, """\ >>>> +AssertionError: 'wrot[195 chars]read 1048576/1048576 bytes at >>>> offset 0\n1 MiB,[46 chars]c)\n' !=3D 'wrot[195 chars]read failed: >>>> Permission denied\n' >>>> +=C2=A0 wrote 524288/524288 bytes at offset 0 >>>> +=C2=A0 512 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) >>>> +=C2=A0 wrote 524288/524288 bytes at offset 524288 >>>> +=C2=A0 512 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) >>>> ++ read failed: Permission denied >>>> +- read 1048576/1048576 bytes at offset 0 >>>> +- 1 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) >>>> + >>> >>> This iotest failing is an intermittent that I've seen running >>> pullreqs on master. I tend to see it on the s390 host. I >>> suspect a race condition somewhere where it fails if the host >>> is heavily loaded. >> It's obviously a failure in an iotest, so let's CC: the >> corresponding people (done now). >>=20 > > Sorry for long delay. > > Does it still fail? > > In the test we expect that copy-before-write operation fails (because > of throttling and timeout), and therefore snapshot is broken and next > read from snapshot should fail. > > But most probably the copy-before-write operation succeeded in this > case for some reason.. I don't think that throttling and timeouts in > block layer can guarantee some determinism.. But usually it works. > > we use throttling with bps-write =3D 300 * 1024, i.e. 300KB per second. a= nd cbw-timeout is set to 1 second. > > Then we do write 512K, > > then the comment say: > # We need second write to trigger throttling > > and we write another 512K. > > first 512K are written, and we should wait 512/300 =3D 1.7 seconds since > _start_ of that write before issuing the second one.. But if write was > slow we may have to wait less than a second from finish of the first > write start the second one. Then timeout will not fire. > > =3D=3D=3D=3D > > I see two possible ways to fix that: > > 1. decrease bps-write a bit. For example to 200 BPS. > > 2. rework the test to use null-co instead of real images. This way we wil= l not suffer from unstable IO duration. > > > So, is the problem still fire sometimes?=09 For me it is random. When it happens, it do it forever. And then it stops, and don't happens for a while. It is not happening for me now. Later, Juan.