Re: FYI: coreutils/gnulib-tests to run in parallel

[Jim Meyering]

Ralf Wildenhues <address@hidden> wrote:
> * Jim Meyering wrote on Fri, Jun 13, 2008 at 09:22:31AM CEST:
>> Just a heads up that I'll soon be making coreutils run its gnulib-tests/
>> in parallel.
>
> Cool.
>
>> Actually, the difference in total run time isn't as great as I'd hoped it
>> would be due to two relatively long-running tests, test-malloca and
>> test-stat-time.
>
> Let them run early.  For GNU make 3.80 or newer, you can use order-only
> dependencies, roughly like
>   $(all_other_logs): | test-stat-time.log test-malloca.log

Thanks for the tip.
I didn't know about that feature.

> Just ordering the build of some huge objects in GCC allowed to shave 30%
> build time off a parallel build:
> <http://gcc.gnu.org/ml/gcc-patches/2008-03/msg01888.html>

Yes, I did the same with coreutils/tests, and it made a big difference,
since there were some long-running tests near the end of the initial list.
Here it was the first thing I tried, once parallelized.  However, in
this case it gave less than 1 second decrease.  No big surprise, though,
since even removing the top 4-5 longest-running tests shaves only ~8
seconds off the total (~11s) run time, now that they're run in parallel.

> Hmm, where to take the time to merge check.mk into Automake ...

:-)