On Tue, Feb 02, 2016 at 05:01:35PM -0500, Russell Bryant wrote: > On 02/02/2016 04:49 PM, Ben Pfaff wrote: > > On Thu, Jan 21, 2016 at 03:21:00PM -0500, Russell Bryant wrote: > >> Previously, ovn-controller translated logical flows into OpenFlow flows > >> for *every* logical datapath. This patch makes it so we skip doing so > >> for the egress pipeline if the datapath is a logical switch with no > >> logical ports bound locally. In that case, the flows have no effect. > >> > >> This was the code path taking the most time in a large scale OVN > >> environment and was an easy optimization to make based on the existing > >> local_datapaths info. > >> > >> In this environment, while idling, ovn-controller was taking up about > >> 20% CPU with this patch, while other nodes were in the 40-70% range. > >> > >> Reported-at: https://bugs.launchpad.net/networking-ovn/+bug/1536003 > >> Signed-off-by: Russell Bryant <russ...@ovn.org> > >> Tested-by: Matt Mulsow <mailto:mamul...@us.ibm.com> > >> --- > >> > >> > >> As discussed in the OVN IRC meeting today, this is one patch I came up > >> with while trying to analyze the performance in a large scale OVN > >> test setup. It made a big impact for not much code. I know Ben had some > >> suggestions for how to clean this up, so I'm just submitting as RFC for > >> now. > > > > I think this is fine for now; we can optimize more later. > > > > However I get a compile error against current master, perhaps it has > > moved on since you posted the patch: > > > > ../ovn/controller/ovn-controller.c: In function ‘main’: > > ../ovn/controller/ovn-controller.c:300:54: error: ‘local_datapaths’ > > undeclared (first use in this function) > > lflow_run(&ctx, &flow_table, &ct_zones, &local_datapaths); > > ^ > > ../ovn/controller/ovn-controller.c:300:54: note: each undeclared > > identifier is reported only once for each function it appears in > > Yeah, I actually wrote this on top of this patch series: > > https://patchwork.ozlabs.org/bundle/russellb/localnet/ > > mainly because the scale test environment had those patches applied. > > > I think that the way to optimize this, in the end, is to use a kind of > > "flood fill" algorithm: > > > > 1. Initialize set S to the logical datapaths that have a port > > located on the hypervisor. > > > > 2. For each patch port P in a logical datapath in S, add the logical > > datapath of the remote end of P to S. > > > > Extra credit if there's a way to infer (or specify) that a logical > > datapath is "terminal", that is, that a packet that comes into it from a > > different logical datapath will never come back out. > > right, because #2 needs to happen on every datapath added as a result of > #2, as well.
Yes, I forgot to mention that #2 iterates until you reach a fixed point. I guess I'll ack this quickly when it reaches non-RFC. _______________________________________________ dev mailing list dev@openvswitch.org http://openvswitch.org/mailman/listinfo/dev
