[ovs-dev] [PATCH] ovn-controller: squelch expected duplicate flow warnings

[Ben Pfaff]

On Wed, Jul 27, 2016 at 09:13:56PM -0500, Ryan Moats wrote:
> 
> 
> Ben Pfaff <blp at ovn.org> wrote on 07/27/2016 03:53:56 PM:
> 
> > From: Ben Pfaff <blp at ovn.org>
> > To: Guru Shetty <guru at ovn.org>
> > Cc: Ryan Moats/Omaha/IBM at IBMUS, ovs dev <dev at openvswitch.org>
> > Date: 07/27/2016 03:54 PM
> > Subject: Re: [ovs-dev] [PATCH] ovn-controller: squelch expected
> > duplicate flow warnings
> >
> > On Tue, Jul 26, 2016 at 01:54:29PM -0700, Guru Shetty wrote:
> > > On 24 July 2016 at 10:07, Ryan Moats <rmoats at us.ibm.com> wrote:
> > >
> > > > In the physical processing of ovn-controller, there are two
> > > > sets of OF flows that are still fully recalculated every cycle:
> > > >
> > > >   Flows that aren't associated with any logical flow, and
> > > >   Flows calculated based on multicast groups
> > > >
> > > > Because these flows are recalculated fully each cycle, full
> > > > duplicates of existing OF flows are created and the OF management
> > > > code in ovn-controller pollutes the logs with false positive
> > > > warnings about repeated duplicates.
> > > >
> > > > As a short term measure, ignore full duplicates for both of
> > > > these types of flows, but still warn if the action changes
> > > > (as that is not expected and may be indicative of a problem).
> > > >
> > > > Signed-off-by: Ryan Moats <rmoats at us.ibm.com>
> > > >
> > >
> > > I also noticed that "commit 70c7cfef188b5ae9940abd5 (ovn-controller:
> Add
> > > incremental processing to lflow_run and physical_run)" causes load
> > > balancing system unit tests to fail. A little debugging shows that
> groups
> > > are getting deleted when new flows are added.  My hunch is that this is
> > > likely because 'desired_groups' in ofctl_put gets deleted in every run.
> But
> > > in the next run, it does not get updated as we no longer process all
> flows.
> >
> > It's unclear to me from the discussion of this patch whether it's
> > beneficial.  Can someone clarify?
> >
> > Thanks,
> >
> > Ben.
> 
> Unfortunately, I don't think we maintained reasonable email thread
> discipline
> on this discussion - for me, the vast majority of the conversation was
> about
> the CPU cycle bug that Guru mentions and not the patch itself.
> 
> The conditions stated in the commit message still apply even after fixing
> Guru's issue and so I still see the squelching as being useful to avoid
> polluting the ovn-controller logs with false positive messages...

I think that you said in IRC that you're dropping this patch.  Let me
know if I'm wrong.

Thanks,

Ben.