On Tue, Feb 02, 2016 at 05:31:42PM -0500, Russell Bryant wrote: > On 02/02/2016 05:21 PM, Ben Pfaff wrote: > > 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. > > > > You can ACK it now if you're happy with it and you'd like to skip the > formality. I was only going to update comment text based on our > discussion here about "flood fill".
Acked-by: Ben Pfaff <b...@ovn.org> _______________________________________________ dev mailing list dev@openvswitch.org http://openvswitch.org/mailman/listinfo/dev
