Thanks Mathieu! I think we should first merge Edouard's patch, which appears to be a prerequisite. I think we could benefit a lot by applying this mechanism to process_network_ports.
However, I am not sure if there could be drawbacks arising from the fact that the agent would assign the local VLAN port (either the lvm id or the DEAD_VLAN tag) and then at the end of the iteration the flow modifications, such as the drop all rule, will be applied. This will probably create a short interval of time in which we might have unexpected behaviours (such as VMs on DEAD VLAN able to communicate each other for instance). I think we can generalize this discussion and use deferred application for ovs-vsctl as well. Would you agree with that? Thanks, Salvatore On 7 January 2014 14:08, Mathieu Rohon <mathieu.ro...@gmail.com> wrote: > I think that isaku is talking about a more intensive usage of > defer_apply_on/off as it is done in the patch of gongysh [1]. > > Isaku, i don't see any reason why this could not be done in > precess_network_ports, if needed. Moreover the patch from edouard [2] > resolves multithreading issues while precessing defer_apply_off. > > > [1]https://review.openstack.org/#/c/61341/ > [2]https://review.openstack.org/#/c/63917/ > > On Mon, Jan 6, 2014 at 9:24 PM, Salvatore Orlando <sorla...@nicira.com> > wrote: > > This thread is starting to get a bit confusing, at least for people with > a > > single-pipeline brain like me! > > > > I am not entirely sure if I understand correctly Isaku's proposal > concerning > > deferring the application of flow changes. > > I think it's worth discussing in a separate thread, and a supporting > patch > > will help as well; I think that in order to avoid unexpected behaviours, > > vlan tagging on the port and flow setup should always be performed at the > > same time; if we get a much better performance using a mechanism similar > to > > iptables' defer_apply, then we should it. > > > > Regarding rootwrap. This 6x slowdown, while proving that rootwrap > imposes a > > non-negligible overhead, it should not be used as a sort of proof that > > rootwrap makes things 6 times worse! What I've been seeing on the gate > and > > in my tests are ALRM_CLOCK errors raised by ovs commands, so rootwrap has > > little to do with it. > > > > Still, I think we can say that rootwrap adds about 50ms to each command, > > becoming particularly penalising especially for 'fast' commands. > > I think the best things to do, as Joe advices, a test with rootwrap > disabled > > on the gate - and I will take care of that. > > > > On the other hand, I would invite community members picking up some of > the > > bugs we've registered for 'less frequent' failures observed during > parallel > > testing; especially if you're coming to Montreal next week. > > > > Salvatore > > > > > > > > On 6 January 2014 20:31, Jay Pipes <jaypi...@gmail.com> wrote: > >> > >> On Mon, 2014-01-06 at 11:17 -0800, Joe Gordon wrote: > >> > > >> > > >> > > >> > On Mon, Jan 6, 2014 at 10:35 AM, Jay Pipes <jaypi...@gmail.com> > wrote: > >> > On Mon, 2014-01-06 at 09:56 -0800, Joe Gordon wrote: > >> > > >> > > What about it? Also those numbers are pretty old at this > >> > point. I was > >> > > thinking disable rootwrap and run full parallel tempest > >> > against it. > >> > > >> > > >> > I think that is a little overkill for what we're trying to do > >> > here. We > >> > are specifically talking about combining many utils.execute() > >> > calls into > >> > a single one. I think it's pretty obvious that the latter will > >> > be better > >> > performing than the first, unless you think that rootwrap has > >> > no > >> > performance overhead at all? > >> > > >> > > >> > mocking out rootwrap with straight sudo, is a very quick way to > >> > approximate the performance benefit of combining many utlils.execute() > >> > calls together (at least rootwrap wise). Also it would tell us how > >> > much of the problem is rootwrap induced and how much is other. > >> > >> Yes, I understand that, which is what the article I linked earlier > >> showed? > >> > >> % time sudo ip link >/dev/null > >> sudo ip link > /dev/null 0.00s user 0.00s system 43% cpu 0.009 total > >> % sudo time quantum-rootwrap /etc/quantum/rootwrap.conf ip link > >> > /dev/null > >> quantum-rootwrap /etc/quantum/rootwrap.conf ip link > /dev/null 0.04s > >> user 0.02s system 87% cpu 0.059 total > >> > >> A very tiny, non-scientific simple indication that rootwrap is around 6 > >> times slower than a simple sudo call. > >> > >> Best, > >> -jay > >> > >> > >> _______________________________________________ > >> OpenStack-dev mailing list > >> OpenStack-dev@lists.openstack.org > >> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev > > > > > > > > _______________________________________________ > > OpenStack-dev mailing list > > OpenStack-dev@lists.openstack.org > > http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev > > > > _______________________________________________ > OpenStack-dev mailing list > OpenStack-dev@lists.openstack.org > http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev >
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