Re: Compile test with gcc 3.2

Hi Mario:
--- Mario Weilguni <mweilguni@sime.com> wrote:
> If you want to get the max (CPU) performance and use
> gcc, you should give the -fprofile-arcs /
> -fbranch-probabilties options of gcc 3.2 a try.
> For 50 pgbench read-only runs (1 mio tuples, 40000
> txs, 10 clients) I get 14.4% speedup.
>
> Then I tried it with real data from our production
> system.
> This is 2GB data, 120 tables, but most of the data
> is large object data (1.8GB), so most tables  of the
> database are in-memory and the application is more
> cpu bound.
> With this scenario, I still get 8% improvement.
>
> All tests done on an Athlon XP/1500, 768MB RAM,
> Linux 2.4.19, gcc 3.2, 5400 RPM Maxtor.
>
> Might be worth a try. Probably the performance win
> will be smaller for larger databases.

 - Do you use the "-fprofile-arcs
-fbranch-probabilties" options with other optimization
flags? I've in a book (Optimimizing Red Hat Linux 6.2)
that one could also optimize speed by setting the
CFLAGS to the following :
  " -02 -fomit-frame-pointers -funroll-loops" and
  running "strip" on the on binaries after they are
compiled.

regards,
ludwig.

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