Inliner parameters

[Richard Guenther]

On 17 Apr 2003, Steven Bosscher wrote:

> Op wo 16-04-2003, om 23:17 schreef Richard Guenther:
> > > When was the last time somebody tried to tune the parameters a bit?  Did
> > > anyone try the effects of different parameter settings for, say, SPEC
> > > and POOMA (and, ideally, on more than one platform)?
> >
> > I tried various parameters for POOMA to tune the performance of the
> > optimized code and the key parameter to change was min-inline-insns.
> > This is _way_ too low for POOMA to collapse the expression template
> > trees. I need to bump this up to 250 to get good performance. The
> > max-inline-insns-single can be dropped to 250 without loss then.
>
> What happened to the compile times with bigger min-inline-insns?

Here are compile time and runtime numbers for my performace testcase using
g++-3.3 (GCC) 3.3 20030414 (prerelease) with options -O2 -march=athlon
-fomit-frame-pointer -funroll-loops -fno-exceptions --param min-inline-insns=X.
Lower numbers for the perf. indicator are better.

  X      compile-time    performance indicator
default     49.50           1.99804e-06
 50         50.25           2.26817e-06
100         50.00           1.96918e-06
150         51.00           1.90269e-06
200         58.25           1.83045e-06
250         61.25           1.28309e-06
300         62.75           1.29364e-06
default + -Dinline="__inline__ __attribute__((always_inline))"
            50.50           1.31171e-06
(while the source is not optimized for inline->always_inline
transformation)

just to show what happens with EH on, for the best param above (250)
we get

250         [again, goes into swap... - till then, 3min elapsed]
killed it - going to a machine with 2GB ram and more GHz where we cant
compare the compile time numbers from above, of course...
250        448.00 [uses 750MB of ram]  5.96641e-07
which is more than an order of magnitude worse than without EH on a
faster CPU with faster mem... ugh!

Richard.

--
Richard Guenther <richard dot guenther at uni-tuebingen dot de>
WWW: http://www.tat.physik.uni-tuebingen.de/~rguenth/