[mpich-discuss] Why is my quad core slower than cluster

[Matthew Bettencourt]

We have the same issue, the issue is memory bandwidth for us.  We can't 
utilize the extra processing power that tht multicore provides because 
we can't keep those cores fed.
M


zach wrote:
> Following up on these suggestions and info queries...
> (Thanks for the help!)
> 
> I noticed my home pc processor is a
> Core2 Quad CPU Q6600  @ 2.40GHz (Kentsfield)
> whereas the cluster Xeon is 3.20GHz.
> I don't think this is causing the degree of 3 in speed.
> 
> compiler is gcc on home pc and cluster.
> 
> same optimization option for both systems
> yes cpuinfo and meminfo show the right #cpus and mem
> 
> mpich is different versions i have discovered.
> 
> on cluster (faster one),
> MPICH Version:    	1.2.7p1
> MPICH Release date:	$Date: 2005/11/04 11:54:51$
> MPICH Patches applied:	none
> MPICH configure: 	--prefix=/opt/mpich/intel --enable-sharedlib
> --with-romio --enable-f90modules -c++=icpc -cc=icc -fc=ifort
> -f90=ifort
> MPICH Device:    	ch_p4
> 
> on home pc (the slug),
> MPICH2 Version:    	1.0.7
> MPICH2 Release date:	Unknown, built on Tue Jul  8 19:28:07 CDT 2008
> MPICH2 Device:    	ch3:nemesis
> MPICH2 configure: 	--prefix=/home/code/mpich --with-device=ch3:nemesis
> MPICH2 CC: 	gcc  -O2
> MPICH2 CXX: 	c++  -O2
> MPICH2 F77: 	
> MPICH2 F90: 	
> 
> on the cluster I have been compiling with mpiCC and on the home pc with mpicxx.
> 
> kernel on home pc:
> Linux myPC 2.6.24-18-generic #1 SMP Wed May 28 19:28:38 UTC 2008
> x86_64 GNU/Linux
> 
> I am using ubuntu hardy and did not use 'sudo' during installation of
> mpich2 (not logged in as superuser) -don't know if this matters.
> 
> zach
> 
>