[ovs-dev] profiling ovn-northd-ddlog

[Ben Pfaff]

Hi Leonid and Mihai (and ovs-dev).

I've been working on profiling ovn-northd-ddlog this week.  I've made my
current work available in my ovs-reviews repo in branch ddlog22, e.g.
in the web interface:
        https://github.com/blp/ovs-reviews/tree/ddlog22

When I run the northd_ddlog_test.sh script inside the sandbox, which can
be started using ddlog with "make sandbox SANDBOXFLAGS=--ddlog", I get
the following replay.txt (actually I've edited it a bit to print "x" on
the console occasionally for feedback) and profile:
https://benpfaff.org/~blp/replay2.txt
https://benpfaff.org/~blp/profile.txt

If I had to guess from a glance at replay2.txt, I'd say that the
repeated deletion and insertion of a growing Port_Group is the root
cause of the slowness here.  If it looks the same way to you, I wonder
whether you have an idea how to work around that?  (Maybe
ovn-north-ddlog needs to present it to ddlog as a table that can be more
granularly modified, rather than as a set?)