Re: [PATCH v1 0/4] Teach 'run' perf script to read config files

[Jeff King <peff@peff.net>]

On Thu, Jul 13, 2017 at 08:57:01PM +0200, Christian Couder wrote:

> >> We want to make it possible to store the parameters to the 'run'
> >> script in a config file. This will make it easier to store, reuse,
> >> share and compare parameters.
> >
> > Because perf-lib is built on test-lib, it already reads
> > GIT-BUILD-OPTIONS.
> 
> Actually the 'run' script also sources GIT-BUILD-OPTIONS, so maybe
> this is not necessary.

Ah, right. The one that comes via perf-lib gets the variables into the
test scripts themselves. But anything "run" would need itself would come
from the source it does itself. And that's where GIT_PERF_MAKE_OPTS has
an effect.

> Also are the variables in GIT-BUILD-OPTIONS exported already?

No, I don't think so. But because both "run" and the scripts themselves
source them, they're available more or less everywhere, except for
sub-processes inside the scripts.

> > And the Makefile copies several perf-related values
> > into it, including GIT_PERF_MAKE_OPTS and GIT_PERF_REPEAT_COUNT. So you
> > can already do:
> >
> >   echo 'GIT_PERF_REPEAT_COUNT = 10' >>config.mak
> >   echo 'GIT_PERF_MAKE_OPTS = CFLAGS="-O2" DEVELOPER=1' >>config.mak
> >   make
> 
> The "make" here might not even be needed as in the 'run' script
> "config.mak" is copied into the "build/$rev" directory where "make" is
> run to build the $rev version.

You need it to bake the config into GIT-BUILD-OPTIONS, which is the only
thing that gets read by "run" and the perf scripts. If you are
just setting MAKE_OPTS to things that your config.mak already sets, then
yes, you can skip that one.

-Peff