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Tsirkin" Subject: Re: [PULL 3/9] tests/migration: Reduce autoconverge initial bandwidth Message-ID: <20200609170017.GD2841@work-vm> References: <20200325131632.311034-1-dgilbert@redhat.com> <20200325131632.311034-4-dgilbert@redhat.com> <20200609123323-mutt-send-email-mst@kernel.org> MIME-Version: 1.0 In-Reply-To: <20200609123323-mutt-send-email-mst@kernel.org> User-Agent: Mutt/1.13.4 (2020-02-15) X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit Content-Disposition: inline Received-SPF: pass client-ip=205.139.110.61; envelope-from=dgilbert@redhat.com; helo=us-smtp-delivery-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/06/09 02:41:53 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] 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_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_PASS=-0.001, T_HK_NAME_DR=0.01 autolearn=_AUTOLEARN 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: vsementsov@virtuozzo.com, maozhongyi@cmss.chinamobile.com, pannengyuan@huawei.com, qemu-devel@nongnu.org, imammedo@redhat.com, philmd@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" * Michael S. Tsirkin (mst@redhat.com) wrote: > On Wed, Mar 25, 2020 at 01:16:26PM +0000, Dr. David Alan Gilbert (git) wrote: > > From: Philippe Mathieu-Daudé > > > > When using max-bandwidth=~100Mb/s, this test fails on Travis-CI > > s390x when configured with --disable-tcg: > > > > $ make check-qtest > > TEST check-qtest-s390x: tests/qtest/boot-serial-test > > qemu-system-s390x: -accel tcg: invalid accelerator tcg > > qemu-system-s390x: falling back to KVM > > TEST check-qtest-s390x: tests/qtest/pxe-test > > TEST check-qtest-s390x: tests/qtest/test-netfilter > > TEST check-qtest-s390x: tests/qtest/test-filter-mirror > > TEST check-qtest-s390x: tests/qtest/test-filter-redirector > > TEST check-qtest-s390x: tests/qtest/drive_del-test > > TEST check-qtest-s390x: tests/qtest/device-plug-test > > TEST check-qtest-s390x: tests/qtest/virtio-ccw-test > > TEST check-qtest-s390x: tests/qtest/cpu-plug-test > > TEST check-qtest-s390x: tests/qtest/migration-test > > ** > > ERROR:tests/qtest/migration-test.c:1229:test_migrate_auto_converge: 'got_stop' should be FALSE > > ERROR - Bail out! ERROR:tests/qtest/migration-test.c:1229:test_migrate_auto_converge: 'got_stop' should be FALSE > > make: *** [tests/Makefile.include:633: check-qtest-s390x] Error 1 > > > > Per David Gilbert, "it could just be the writing is slow on s390 > > and the migration thread fast; in which case the autocomplete > > wouldn't be needed. Perhaps we just need to reduce the bandwidth > > limit." > > > > Tuning the threshold by reducing the initial bandwidth makes the > > autoconverge test pass. > > > > Suggested-by: Dr. David Alan Gilbert > > Signed-off-by: Philippe Mathieu-Daudé > > Message-Id: <20200323184015.11565-1-philmd@redhat.com> > > Reviewed-by: Dr. David Alan Gilbert > > Tested-by: Alex Bennée > > Signed-off-by: Dr. David Alan Gilbert > > > This slows make check down significantly for me, it stays > at the migration test for minutes. Is this on the s390x version or all of them? > I'm carrying a revert at top of my tree for now but I'd rather > not need that. > > > This seems like a fragile way to test things anyway. > What happens if someone slows writing even more > e.g. because it's running in a container or a VM? > > How about detecting that migration finished too early > and slowing it down until autocomplete triggers? THe problem is you can't rely on any form of consistency in a heavily contended container, so the fact that it took n-seconds to migrate at this attempt means very little about what the next attempt will take. Dave > > > > --- > > tests/qtest/migration-test.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/tests/qtest/migration-test.c b/tests/qtest/migration-test.c > > index 3d6cc83b88..2568c9529c 100644 > > --- a/tests/qtest/migration-test.c > > +++ b/tests/qtest/migration-test.c > > @@ -1211,7 +1211,7 @@ static void test_migrate_auto_converge(void) > > * without throttling. > > */ > > migrate_set_parameter_int(from, "downtime-limit", 1); > > - migrate_set_parameter_int(from, "max-bandwidth", 100000000); /* ~100Mb/s */ > > + migrate_set_parameter_int(from, "max-bandwidth", 1000000); /* ~1Mb/s */ > > > > /* To check remaining size after precopy */ > > migrate_set_capability(from, "pause-before-switchover", true); > > -- > > 2.25.1 > > > > > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK