Subject: Re: f2c-960717-0 uploaded to master

From: [email-masked]
Date: Thu, 1 Aug 1996 01:05:56 -0400

>Could you provide a reference to these benchmarks, and the compiler settings
>they used? Or better yet, even run them?  I don't really use fortran myself,
>but link some of my C++ code with Fortran libraries that other folks have
>done. But I could do with a speedup of factor 2 ...

see the following web-site
http://nils.wustl.edu/schiotz/lapack-linux.html

(this is a partial quote)
PERFORMANCE:

I have compared the speed of the level 3 BLAS routines, using a benchmark program I found on
Netlib. I ran it using Dave Webers f2c+gcc compiled library, and also using g77 compiled static and
dynamic libraries. Here are the results, obtained on a 75MHz Pentium PC from Gateway2000. 

                           ------- Speed in Megaflops -------
Routine                 f2c+gcc         g77             g77
                        (shared)        (shared)        (static)
=================================================================
DSYMM                   2.9             5.3             5.6
DSYRK                   2.7             5.5             5.6
DSYR2K                  3.2             6.0             6.0
DTRMM                   2.6             4.6             5.1
DTRSM                   2.4             4.1             4.5
-----------------------------------------------------------------
Average                 2.76            5.10            5.36
-----------------------------------------------------------------
rel. to f2c+gcc         100%            185%            194%
rel. to g77(sh)         54%             100%            105%
rel. to g77(st)         51%             95%             100%
=================================================================
So I see almost a factor two increase in performance! I also see the expected 5% penalty of the
shared libraries, coming from losing one register.

---

From: [email-masked]
Date: Thu, 1 Aug 96 01:39 EDT

Right, I know that lapack-linux website too. Note gcc-2.7.0 and g77-0.5.17
were used, more recent ones are available. g77 got better with 0.5.18, but
also slower (according to some very casual measurements I did on one piece of
code). Also, Jacob Schiotz doesn't say anything about compiler versions.

It would be good if someone had some time to redo these and some others
benchmarks.

-- 
Dirk Eddelb"uttel                             http://qed.econ.queensu.ca/~edd