Re: openmp

[skaller]

On Sat, 13 Oct 2007 20:30:52 -0700, Paul Pluzhnikov wrote:

> skaller <skaller@users.sf.net> writes:
> 
>> So which version of g++ first provides openmp support?
> 
> From http://gcc.gnu.org/gcc-4.2/changes.html:
>   OpenMP is now supported for the C, C++ and Fortran compilers.

hum ... well I tried this on my amd64x2 machine. A test case
for LU decomposition, dimension 800:

1 thread: 4.7 seconds
2 threads: 13 seconds

Well then I discovered the stupid program was using 'clock()' function.
Which counts the time for BOTH processors!

So I used the time command .. and the threaded version is STILL slower.

BTW: running Linux rt patched kernel..


-- 
John Skaller <skaller at users dot sf dot net>
Try Felix, the successor to C++ http://felix.sf.net