[gmx-users] --enable-threads fails.

[Erik Lindahl]

Hi,

The prefetching hardware is pretty good at hiding latencies, but  
obviously you'll get better performance when everything fits in cache.

However, the largest data structures by far are the neighborlists,  
and their _total_ size for the simulation is independent of whether  
you are using multiple processes or multithreading.

Cheers,

Erik

On Apr 10, 2007, at 10:46 PM, vipin sachdeva wrote:

>
> Thanks. Do you see L2 cache overflowing effects by putting multiple  
> MPI processes on the same chip with the recent multi-core processors
> (Intel Woodcrest for  instance)?
>
>
> Regards
> vipin
>
>
>
>
> On Tue, 10 Apr 2007, Erik Lindahl wrote:
>
>> Hi,
>>
>> On Apr 10, 2007, at 10:15 PM, vipin sachdeva wrote:
>>> This thread on Feb 8 2006 mentions that threads are not yet  
>>> functional.
>>> http://www.gromacs.org/pipermail/gmx-users/2006-February/019760.html
>>> Is the threads still not functional considering I still get the  
>>> same error ?
>>
>> We are only using threads for experimental development of the  
>> nonbonded interaction loop. The multi-level-cache-locality  
>> features on modern CPUs (even NUMA on Opterons) means that you  
>> normally get better performance by partitioning the problem into  
>> separate MPI processes, where each process resides on a separate  
>> core.
>>
>> Cheers,
>>
>> Erik
>>
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