[ovs-dev] [PATCH v3 9/9] ovn-trace: New utility.

[Ryan Moats]

Ben Pfaff <blp at ovn.org> wrote on 08/08/2016 11:56:22 PM:

> From: Ben Pfaff <blp at ovn.org>
> To: Ryan Moats/Omaha/IBM at IBMUS
> Cc: dev at openvswitch.org
> Date: 08/08/2016 11:57 PM
> Subject: Re: [ovs-dev] [PATCH v3 9/9] ovn-trace: New utility.
>
> On Mon, Aug 08, 2016 at 09:33:54PM -0500, Ryan Moats wrote:
> > "dev" <dev-bounces at openvswitch.org> wrote on 08/08/2016 01:21:52 PM:
> >
> > > From: Ben Pfaff <blp at ovn.org>
> > > To: dev at openvswitch.org
> > > Cc: Ben Pfaff <blp at ovn.org>
> > > Date: 08/08/2016 01:23 PM
> > > Subject: [ovs-dev] [PATCH v3 9/9] ovn-trace: New utility.
> > > Sent by: "dev" <dev-bounces at openvswitch.org>
> > >
> > > This new utility is intended to fulfill for OVN the purpose that
> > > "ofproto/trace" has for Open vSwitch.  First, it's meant to be a
useful
> > > tool for troubleshooting and diagnosis and in general for improving
one's
> > > understanding of the emergent properties of a flow table.  Second, it
> > > simplifies and increases the practical scope of testing, as well as
> > making
> > > testing more reliable and repeatable and failures easier to
interpret.
> > >
> > > This commit adds only a single test that uses the new utility, based
on
> > the
> > > oldest OVN end-to-end test "ovn -- 3 HVs, 1 LS, 3 lports/HV".  The
> > > differences between the old and the new test illustrate properties of
> > > tracing.  First, the new test does not start any ovn-controller
processes
> > > or simulate any hypervisors in a nontrivial way.  This is because
> > ovn-trace
> > > does not actually forward packets or rely on the physical structure
of
> > the
> > > system.  Second, whereas the old test tested not just the logical but
> > also
> > > the physical structure of the system, it needed to have several
logical
> > > ports, a total of 9 (3 on each of 3 HVs), whereas since this test
only
> > > tests the logical network implementation it can use a smaller number.
> > This
> > > property also means that the new test runs signicantly faster than
the
> > old
> > > one (less than a second on my laptop).
> > >
> > > In my opinion this approach points the way toward the future of OVN
> > > testing.  Certainly, we need end-to-end tests.  However, I believe
that
> > the
> > > bulk of our tests can be broken into ones that test the logical
network
> > > implementation (using tracing) and ones that test physical/logical
> > > translation.
> > >
> > > Signed-off-by: Ben Pfaff <blp at ovn.org>
> > > ---
> >
> > Rather than dribs and drabs, let's just ack the whole rest of the
> > series (it took me longer because there was a bunch of code to read
> > through and understand)
> >
> > Acked-by: Ryan Moats <rmoats at us.ibm.com>
>
> Thanks for all the reviews!
>
> I've asked Justin to have a second look at patches 2 and 9 in
> particular.  I guess that this will take him a day or so.
>

That's fair - it was those two that took me the longest...