I don't know what is changed.. but I partially resolved the problem:
is not an hardware problem (installing smp kernel it works).
Now I've to use mpirun (before I didn't use it), and I don't succeed to
tell the system to use both processors for only one process.
In fact using "mpirun -c 2" it makes two processes, each for one cpu.
I need to work with only one process, and before I succeeded in this.
(with another computer dual core I'm able to do this.
Thanks
Andrew Friedley ha scritto:
> Beniamino Sciacca wrote:
>
>> Hi community!
>> I've a great problem:
>> two months ago I installed LAM on my centrino duo, debian -kernel 2.6.
>> Later I compiled gromacs enabling mpi, and everything was working well
>> until four days ago.
>> Now the simulation time is increased like if there is only one processor
>> (it takes twice time than before).
>> I don't understand why.
>> I disinstalled and then reinstalled LAM and gromacs (LAM 7.1.2 (I
>> compiled it on my own) + gromacs 3.3.1).
>> Nothing has changed.
>> I disinstalled linux and then reinstalled (debian kernel 2.6), and again
>> LAM and gromacs: I've the same problem, like if one of the two cores
>> doesn't work.
>> I tried also to install gromacs NON mpi-enabled, and I've the same
>> simulation time (respect to the enabled-mpi gromacs).
>> In all these cases LAM seems to work (when I type lamboot LAM starts
>> without problem).
>>
>> What's happened?
>> How can I understand if it's a software problem or an hardware one?
>> thank you very much for the reply!
>>
>
> The first question I always ask is - what changed? You say it was
> working properly up to some point, something must have happened at or
> before that point.
>
> It's hard to tell based on the information you've given, but the first
> thing I would do is make sure linux has both CPU's enabled, and that any
> power management stuff isn't affecting your performance.
>
> Can you test any other applications, to see if this problem is specific
> to LAM/gromacs?
>
> You might consider other support channels as well - I can't recommend a
> good place for you off the top of my head, but LAM is not likely the
> problem here.
>
> Andrew
> _______________________________________________
> This list is archived at http://www.lam-mpi.org/MailArchives/lam/
>
>
|
