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- To: gcc-help at gcc dot gnu dot org
- Subject: gcc_debian_linux_code_on_freebsd
- From: Hans Weber <weber at mt dot luth dot se>
- Date: Tue, 23 May 2000 08:56:17 +0200
I have a rather odd problem with gcc. (version 2.95.1)
My question is How can I get faster code from freebsd gcc compiler?
Code compiled on a Debian linux machine (installed feb 2000) with
gcc (2.95) is 20 % faster on my freebsd machine compared to if
I compile on my freebsd machines gcc (2.95.1) and then run it on
my freebsd machine. I have linux compat enabled.
I would like to get at least equally fast code from gcc freebsd as I get
from gcc on debian code run on freebsd.
The program is a molecular dynamics program doing lots of floats.
The times are typically (test runs):
compiled and run on freebsd 36 seconds
compiled on debian and run on freebsd 30 seconds
Compile is done with on both debian and freebsd.
gcc -O -o langevin langevin.c -lm
I have checked out the gcc compiler options on
and tried several combinations of them on my gcc freebsd
but I never get below 34.5 seconds.
Not near the debian-gcc code performance on freebsd.
I have tried some tricks with setenv and a variable with
lots of characters this can result in (I got this from tip from a
compiled and run on freebsd becoming 34.5 seconds
and these are the includes in my program.
# include <stdio.h>
# include <math.h>
# include <stdlib.h>
# include <limits.h>
I have just added smp and taken out i386 and i486 from build
fysik3 102> cat motd
FreeBSD 4.0-RELEASE (SMPKERNEL) #1: Tue May 9 13:24:58 CEST 2000
I downloaded the FreeBSD in the beginning of May.
Department of Physics
Luleň University of Technology