On Fri, Jul 12, 2019 at 1:08 PM Leonid Ryzhyk <ryz...@gmail.com> wrote:
> Dear OVN developers, > > This is a brief update on the state of the DDlog port of ovn-northd. > > We completed the initial implementation of ovn-northd in DDlog few months > ago. Justin kindly > helped to integrate it with OVN, so that it can be used as a drop-in > replacement for the C > version (and passes all the tests in the OVN test suite). The DDlog > implementation does > not have any of the new features/improvements added in April 2019 or later. > > ## Repository > > The code is in the `ddlog-dev` branch of the `ovn-org/ovn` repository: > https://github.com/ovn-org/ovn/tree/ddlog-dev > > ## Documentation > > Building and using ovn-northd-ddlog: > https://github.com/ovn-org/ovn/blob/ddlog-dev/ovn/northd/docs/design.md > > Debugging ovn-northd-ddlog: > https://github.com/ovn-org/ovn/blob/ddlog-dev/ovn/northd/docs/debugging.md > > ## Preliminary performance results > > Han Zhou kindly tested ovn-northd-ddlog with his OVN scale test and even > found a nasty > performance bug in the process (thanks, Han!). He reports that DDlog > speeds up the test > by almost a factor of 10: > > - ddlog version: 7:39min > - C version: 67:47min > > This is great, and in fact profiling shows that there is still plenty of > space for > improvement. He also reports a 10+ times increase in memory footprint: > > - ddlog version: 1944696KB > - C version: 147984KB > > Again, we are working on a number of optimizations, which should reduce > this overhead; although it will never be as low as C, since DDlog > fundamentally > needs to cache more state to enable fast incremental computation. > > Han also used DDlog's record&replay feature to capture all northd > transactions > performed by the scale test in a format that can be replayed against the > standalone DDlog executable without having to reproduce Han's OpenStack > setup. > The replay file is here: http://ryzhyk.net/replay.tgz > > Instructions for replaying this script: > > https://github.com/ovn-org/ovn/blob/ddlog-dev/ovn/northd/docs/debugging.md#record-and-replay-ddlog-execution > The script will run for a few > minutes and finally print some profiling information, including the > breakdown of > DDlog's CPU and memory usage. > > ## Next steps > > We seek help from the OVN community in maintaining ovn-northd-ddlog. The > first > step is to start porting new OVN features introduced in the last few months > to > DDlog. > > Thanks Leonid for the updates and the instructions. Right now I am working on some of the other OVN stuff. After that I will definitely try it out. Thanks Numan > Leonid > _______________________________________________ > dev mailing list > d...@openvswitch.org > https://mail.openvswitch.org/mailman/listinfo/ovs-dev > _______________________________________________ dev mailing list d...@openvswitch.org https://mail.openvswitch.org/mailman/listinfo/ovs-dev
