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

[Christian Couder <christian.couder@gmail.com>]

On Thu, Jul 13, 2017 at 6:58 PM, Jeff King <peff@peff.net> wrote:
> On Thu, Jul 13, 2017 at 08:50:46AM +0200, Christian Couder wrote:
>
>> Goal
>> ~~~~
>>
>> Using many long environment variables to give parameters to the 'run'
>> script is error prone and tiring.
>>
>> 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.
Also are the variables in GIT-BUILD-OPTIONS exported already?

> 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.

>   cd t/perf
>   ./run <versions-and-scripts>
>
> I suspect there are still a lot of things that could be made easier with
> a config file, so I'm not against the concept. Your example here:
>
>> [perf "with libpcre"]
>>         makeOpts = DEVELOPER=1 CFLAGS='-g -O0' USE_LIBPCRE=YesPlease
>> [perf "without libpcre"]
>>         makeOpts = DEVELOPER=1 CFLAGS='-g -O0'
>
> is a lot more compelling. But right now the perf suite is not useful at
> all for comparing two builds of the same tree. For that, I think it
> would be more useful if we could define a tuple of parameters for a run.
> One of which could be the tree we're testing. Build opts are another.
> Tested repository is another. And then we'd fill in a table of results
> and let you slice up the table by any column (e.g., compare times for
> runs against a single tree but with differing build options).

Yeah, improving the output part is another thing that I have discussed
with AEvar and that I have planned to work on.