Experimenting with tree inliner parameter settings

[Andreas Jaeger]

Steven Bosscher <s.bosscher@student.tudelft.nl> writes:

> Hello,
>
> Andreas Jaeger and I have spent a few cycles this weekend to
> see what the effect is of different tree inline parameters on
> the compile time performance of GCC and the runtime performace
> of the binaries produced by GCC.  This wasn't exactly a
> scientifically responsible investigation; it is just an
> attempt to find appropriate default values for the inliner
> parameters.
>
> Andreas has tested 20 different sets of parameters with
> SPECint2000, compiler was GCC 3.4 20030502 CVS.  All tests
> were done with the same compiler, i.e. the compiler was not
> bootstrapepd with these param settings.  Here are the results
> (non-reportable; built once; two runs per test;
> flags: -O2 -march=athlon):
>
> 1 = max-inline-insns-single == max-inline-insns-auto
> 2 = max-inline-insns
> 3 = min-inline-insns
> 4 = max-inline-slope

The interesting thing is that the final SPEC value stays the same but
some tests improve, others regress:
   164.gzip          1400       292       479*     1400       286       489*
   176.gcc           1100       293       375*     1100       299       368*
   252.eon           1300       232       560*     1300       229       567*
So, the "optimal" value for SPEC is still not found.

Andreas
-- 
 Andreas Jaeger
  SuSE Labs aj@suse.de
   private aj@arthur.inka.de
    http://www.suse.de/~aj