Performance testing framework

[Douglas Bagnall]

A while ago I wrote:

> https://www.samba.org/~dbagnall/perf-tests/
>
> [...]
>
> The next trick I am working on is to run the tests multiple times and
> use the fastest. Then I'll look at regular automatic testing of master.

I did those things. The picture at the URL below tracks a years worth
of performance, looking at the autobuild-tagged commit closest to each
Saturday (in some timezone). Each test run is completed 3 times, and
the fastest result is used. I don't know why there are only two
results from January.

https://www.samba.org/~dbagnall/perf-tests/master-52-weeks.html

If you've been following along this may be rather uninteresting. It
again shows we suddenly got faster in a number of tests -- these tests
were designed to show that we got faster there. Nevertheless the
overall picture is good. Nowhere in this limited subset of AD
functionality have we got slower in master over the last year. Some
areas, like search, look like they have been getting quietly faster
over several weeks.

My next plans for this, if I get time, are to set up a cron job that
will keep this graph up to date, and switch to using some kind of
modern javascript chart that is easier to unpick. Anyone who wants me
to test the performance of other parts of Samba should send patches.
The tests should look just like selftest tests that aren't going to
fail and that take a measurable number of seconds to run.

cheers,
Douglas