Hi: As per irc meeting discussion, some nice findings were already discussed by Numan (Thanks for sharing the details). When changing external_ids for a claimed port e.g. ovn-nbctl set logical_switch_port sw0-port1 external_ids:foo=bar triggers re-computation on local compute. I do see the same behavior. Numan is proposing a patch to skip computation for external_ids column for an already claimed port for port_binding table because of runtime_data, can't handle change for input SB_port_binding, fall back to recompute ( https://github.com/openvswitch/ovs/blob/master/ovn/lib/inc-proc-eng.h#L77). However, I don't see external_ids in port_binding table for the port being set explicitly when setting Interface table in the test code that Daniel posted [1] which could trigger extra re-computation in current test scenario.
Also ovs-vsctl add-br test will also trigger re-computation on local compute and yes I can see the same. Since we don't have any handlers for Ports and Interfaces table similar to port_binding and other handlers @ https://github.com/openvswitch/ovs/blob/master/ovn/controller/ovn-controller.c#L1769, adding a new bridge also causes re-computation on the local compute. Not sure if its required immediately because as per the patch shared by Daniel [1], I don't see any new test bridges getting created apart from br-int and hence wont be much impact. Or may be I missed to see if they are also creating test bridges during testing. Of course, any new ovs-vsctl command for attaching/detaching vif will sure trigger recompute on br-int as and when VIF(vm) gets added/deleted to program the flow on local compute. I didn't get a chance to verify when a chassisredirect port is claimed on a gateway chassis, it triggers computation on all computes registered with SB as per code https://github.com/openvswitch/ovs/blob/master/ovn/controller/binding.c#L722 which was also raises further optimization for chassisredirect flow that Numan is suggesting. 1. https://github.com/danalsan/browbeat/commit/0ff72da52ddf17aa9f7269f191eebd890899bdad On Fri, Jun 21, 2019 at 12:32 AM Han Zhou <[email protected]> wrote: > > > On Thu, Jun 20, 2019 at 11:42 PM Numan Siddique <[email protected]> > wrote: > > > > > > > > On Fri, Jun 21, 2019, 11:47 AM Han Zhou <[email protected]> wrote: > >> > >> > >> > >> On Tue, Jun 11, 2019 at 9:16 AM Daniel Alvarez Sanchez < > [email protected]> wrote: > >> > > >> > Thanks a lot Han for the answer! > >> > > >> > On Tue, Jun 11, 2019 at 5:57 PM Han Zhou <[email protected]> wrote: > >> > > > >> > > > >> > > > >> > > > >> > > On Tue, Jun 11, 2019 at 5:12 AM Dumitru Ceara <[email protected]> > wrote: > >> > > > > >> > > > On Tue, Jun 11, 2019 at 10:40 AM Daniel Alvarez Sanchez > >> > > > <[email protected]> wrote: > >> > > > > > >> > > > > Hi Han, all, > >> > > > > > >> > > > > Lucas, Numan and I have been doing some 'scale' testing of > OpenStack > >> > > > > using OVN and wanted to present some results and issues that > we've > >> > > > > found with the Incremental Processing feature in > ovn-controller. Below > >> > > > > is the scenario that we executed: > >> > > > > > >> > > > > * 7 baremetal nodes setup: 3 controllers (running > >> > > > > ovn-northd/ovsdb-servers in A/P with pacemaker) + 4 compute > nodes. OVS > >> > > > > 2.10. > >> > > > > * The test consists on: > >> > > > > - Create openstack network (OVN LS), subnet and router > >> > > > > - Attach subnet to the router and set gw to the external > network > >> > > > > - Create an OpenStack port and apply a Security Group (ACLs > to allow > >> > > > > UDP, SSH and ICMP). > >> > > > > - Bind the port to one of the 4 compute nodes (randomly) by > >> > > > > attaching it to a network namespace. > >> > > > > - Wait for the port to be ACTIVE in Neutron ('up == True' in > NB) > >> > > > > - Wait until the test can ping the port > >> > > > > * Running browbeat/rally with 16 simultaneous process to > execute the > >> > > > > test above 150 times. > >> > > > > * When all the 150 'fake VMs' are created, browbeat will delete > all > >> > > > > the OpenStack/OVN resources. > >> > > > > > >> > > > > We first tried with OVS/OVN 2.10 and pulled some results which > showed > >> > > > > 100% success but ovn-controller is quite loaded (as expected) > in all > >> > > > > the nodes especially during the deletion phase: > >> > > > > > >> > > > > - Compute node: https://imgur.com/a/tzxfrIR > >> > > > > - Controller node (ovn-northd and ovsdb-servers): > https://imgur.com/a/8ffKKYF > >> > > > > > >> > > > > After conducting the tests above, we replaced ovn-controller in > all 7 > >> > > > > nodes by the one with the current master branch (actually from > last > >> > > > > week). We also replaced ovn-northd and ovsdb-servers but the > >> > > > > ovs-vswitchd has been left untouched (still on 2.10). The > expected > >> > > > > results were to get less ovn-controller CPU usage and also > better > >> > > > > times due to the Incremental Processing feature introduced > recently. > >> > > > > However, the results don't look very good: > >> > > > > > >> > > > > - Compute node: https://imgur.com/a/wuq87F1 > >> > > > > - Controller node (ovn-northd and ovsdb-servers): > https://imgur.com/a/99kiyDp > >> > > > > > >> > > > > One thing that we can tell from the ovs-vswitchd CPU > consumption is > >> > > > > that it's much less in the Incremental Processing (IP) case > which > >> > > > > apparently doesn't make much sense. This led us to think that > perhaps > >> > > > > ovn-controller was not installing the necessary flows in the > switch > >> > > > > and we confirmed this hypothesis by looking into the dataplane > >> > > > > results. Out of the 150 VMs, 10% of them were unreachable via > ping > >> > > > > when using ovn-controller from master. > >> > > > > > >> > > > > @Han, others, do you have any ideas as of what could be > happening > >> > > > > here? We'll be able to use this setup for a few more days so > let me > >> > > > > know if you want us to pull some other data/traces, ... > >> > > > > > >> > > > > Some other interesting things: > >> > > > > On each of the compute nodes, (with an almost evenly distributed > >> > > > > number of logical ports bound to them), the max amount of > logical > >> > > > > flows in br-int is ~90K (by the end of the test, right before > deleting > >> > > > > the resources). > >> > > > > > >> > > > > It looks like with the IP version, ovn-controller leaks some > memory: > >> > > > > https://imgur.com/a/trQrhWd > >> > > > > While with OVS 2.10, it remains pretty flat during the test: > >> > > > > https://imgur.com/a/KCkIT4O > >> > > > > >> > > > Hi Daniel, Han, > >> > > > > >> > > > I just sent a small patch for the ovn-controller memory leak: > >> > > > https://patchwork.ozlabs.org/patch/1113758/ > >> > > > > >> > > > At least on my setup this is what valgrind was pointing at. > >> > > > > >> > > > Cheers, > >> > > > Dumitru > >> > > > > >> > > > > > >> > > > > Looking forward to hearing back :) > >> > > > > Daniel > >> > > > > > >> > > > > PS. Sorry for my previous email, I sent it by mistake without > the subject > >> > > > > _______________________________________________ > >> > > > > discuss mailing list > >> > > > > [email protected] > >> > > > > https://mail.openvswitch.org/mailman/listinfo/ovs-discuss > >> > > > >> > > Thanks Daniel for the testing and reporting, and thanks Dumitru for > fixing the memory leak. > >> > > > >> > > Currently ovn-controller incremental processing only handles below > SB changes incrementally: > >> > > - logical_flow > >> > > - port_binding (for regular VIF binding NOT on current chassis) > >> > > - mc_group > >> > > - address_set > >> > > - port_group > >> > > - mac_binding > >> > > > >> > > So, in test scenario you described, since each iteration creates > network (SB datapath changes) and router ports (port_binding changes for > non VIF), the incremental processing would not help much, because most > steps in your test should trigger recompute. It would help if you create > more Fake VMs in each iteration, e.g. create 10 VMs or more on each LS. > Secondly, when VIF port-binding happens on current chassis, the > ovn-controller will still do re-compute, and because you have only 4 > compute nodes, so 1/4 of the compute node will still recompute even when > binding a regular VIF port. When you have more compute nodes you would see > incremental processing more effective. > >> > > >> > Got it, it makes sense (although then worst case, it should be at > >> > least what we had before and not worse but it can also be because > >> > we're mixing version here: 2.10 vs master). > >> > > > >> > > However, what really worries me is the 10% VM unreachable. I have > one confusion here on the test steps. The last step you described was: - > Wait until the test can ping the port. So if the VM is not pingable the > test won't continue? > >> > > >> > Sorry I should've explained it better. We wait for 2 minutes to the > >> > port to respond to pings, if it's not reachable then we continue with > >> > the next port (16 rally processes are running simultaneously so the > >> > rest of the process may be doing stuff at the same time). > >> > > >> > > > >> > > To debug the problem, the first thing is to identify what flows are > missing for the VMs that is unreachable. Could you do ovs-appctl > ofproto/trace for the ICMP flow of any VM with ping failure? And then, > please enable debug log for ovn-controller with ovs-appctl -t > ovn-controller vlog/set file:dbg. There may be too many logs so please > enable it for as short time as any VM with ping failure is reproduced. If > the last step "wait until the test can ping the port" is there then it > should be able to detect the first occurrence if the VM is not reachable in > e.g. 30 sec. > >> > > >> > We'll need to hack a bit here but let's see :) > >> > > > >> > > In the ovn-scale-test we didn't have data plane test, but this > problem was not seen in our live environment either, with a far larger > scale. The major difference in your test v.s. our environment are: > >> > > - We are runing with an older version. So there might be some > rebase/refactor problem caused this. To eliminate this, I'd suggest to try > a branch I created for 2.10 ( > https://github.com/hzhou8/ovs/tree/ip12_rebase_on_2.10), which matches > the base test you did which is also 2.10. It may also eliminate > compatibility problem, if there is any, between OVN master branch and OVS > 2.10 as you mentioned is used in the test. > >> > > - We don't use Security Group (I guess the ~90k OVS flows you > mentioned were mainly introduced by the Security Group use, if all ports > were put in same group). The incremental processing is expected to be > correct for security-groups, and handling it incrementally because of > address_set and port_group incremental processing. However, since the > testing only relied on the regression tests, I am not 100% sure if the test > coverage was sufficient. So could you try disabling Security Group to rule > out the problem? > >> > > >> > Ok will try to repeat the tests without the SGs. > >> > > > >> > > Thanks, > >> > > Han > >> > > >> > Thanks once again! > >> > Daniel > >> > >> Hi Daniel, > >> > >> Any updates? Do you still see the 10% VM unreachable > >> > >> > >> Thanks, > >> Han > > > > > > Hi Han, > > > > As such there is no datapath impact. After increasing the ping wait > timeout value from 120 seconds to 180 seconds its 100% now. > > > > But the time taken to program the flows is too huge when compared to OVN > master without IP patches. > > Here is some data - http://paste.openstack.org/show/753224/ . I am > still investigating it. I will update my findings in some time. > > > > Please see the times for the action - vm.wait_for_ping > > > > Thanks Numan for the investigation and update. Glad to hear there is no > correctness issue, but sorry for the slowness in your test scenario. I > expect that the operations in your test trigger recomputing and the worst > case should be similar performance as withour I-P. It is weird that it > turned out so much slower in your test. There can be some extra overhead > when it tries to do incremental processing and then fallback to full > recompute, but it shouldn't cause that big difference. It might be that for > some reason the main loop iteration is triggered more times unnecessarily. > I'd suggest to compare the coverage counter "lflow_run" between the tests, > and also check perf report to see if the hotspot is somewhere else. (Sorry > that I can't provide full-time help now since I am still on vacation but I > will try to be useful if things are blocked) > _______________________________________________ > discuss mailing list > [email protected] > https://mail.openvswitch.org/mailman/listinfo/ovs-discuss >
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