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

[Darius Buntinas]

But the kernel is not doing the memcpy.  The memcpy used in mpich2 for 
intel x64_64 is from libc.  Scott, do you know if there is a problem 
with libc memcpy also?

-d

On 07/10/2008 09:00 AM, Scott Atchley wrote:
> On Jul 8, 2008, at 12:35 PM, zach wrote:
> 
>> I am using a cluster.
>> Each pc has two cpus and they are Xeon. Each cpu has 4GB, i think red
>> hat is running.
>>
>> I also use a pc at home- quad core intel chip, 8gb ram, ubuntu.
>>
>> Both are using mpich.
>>
>> I have found that my home pc is only running about 1/3 the speed of
>> the cluster, and the number of processes (4) and code is the same.
>>
>> Can anyone tell me if this is typical, and why, or am I not optimizing
>> something properly?
>>
>> Thanks
>> Zach
> 
> Which processor (Harpertown?). Which kernel?
> 
> Kernels <= 2.6.20 use the wrong memory copy routine for Intel Core2 
> cpus. Since all of your communication will use memory copy, it will make 
> a difference.
> 
> Scott
>