MultiDatabase shard count limitations

[Olly Betts]

On Sun, Aug 23, 2020 at 11:12:39PM +0000, Eric Wong wrote:
> Olly Betts <olly at survex.com> wrote:
> > If most (or at least a significant amount) is CPU time then it would
> > be useful to profile to see if there are any low-hanging fruit.  I've
> > been mostly using the profiler in gperftools lately if you want to
> > try this and don't know what to use.
> 
> Haven't tried gperftools, but I'm somewhat familiar with Linux `perf`.
> Just installed the -dbgsym packages from Debian, attached is
> "perf record ... && perf report" output.

The report you show seems to be just the time take by each function
directly rather than including functions it calls.  It looks like a lot
of the time is spent in cursor movement, as totalling up things that
seem like they'd be due to that I quickly get to 40+% but it's hard
to tell if that's about the actual total or if this is really where
almost all time is spent.  If it were 50% then getting rid of it all
would only halve the time which would be a nice speedup, but still
too slow for your case (and some cursor movement is required as that's
how we skip ahead in posting lists).

Can prof report time for a function including things it calls?

Cheers,
    Olly