Discussion related to cado-nfs

[Emmanuel Thomé <Emmanuel.Thome@inria.fr>]

Hi.

Thanks for your feedback.

This is the annoying bit:

2 nodes, no common name prefix                                                
  
 10  .  .  .  .  .  .                                                         
  
  .  .  .  .  .  .  .                                                         
  
 10  .  .  .  .  .  .                                                         
  
  .  .  .  .  .  .  .                                                         
  
cpubinding: parameter ignored (no hwloc, no C++11)                            
  

You're essentially using the same node twice. I guess that CPU usage on
the second node was ridiculous.

Also, in order to enable cpu binding, you need a c++11 compiler (for gcc,
we're happy with version 4.8 or later).

Please make sure you use the git version, but I think it's the case.

Note that I've never really paid attention to mpich integration. I'm
entirely to blame about that. Hopefull your feedback from fruther trials
will help improve this situation.

You may want to give a try to a more recent compiler, because that should
be the key to giving you the cpu binding code (for no good reason, really
-- I was just lazy on that one). But that's really an aside, because the
main oddity you're facing is elsewhere. I'm a bit puzzled by the fact
that cado-nfs chose to put two jobs on the same node.

What do you have in the following file ?

/home/cado/cado_mpi/share/cado-nfs-2.2.1/dlp/host_file

Also, is your job running from a job scheduler or not ?

E.


On Wed, Mar 29, 2017 at 08:36:58PM +0300, Христофор Бобров wrote:
> Hello! 
> I tried to parallelize the linear phase using MPI. For the number of 87 
> decimal digits, I solved the system on one and two and three nodes, there 
> was no performance increase, for all cases the performance was "krylov: N = 
> 1000; ETA (N = 63000): [0.056 s / iter]
> I ran with cpubinding = false. During the operation, the network was not 
> 100% loaded. What could be the problem?
> I attach to the letter files with stdout bwc.pl for one and two nodes.
> -- 
> Best regards
> Бобров Х.



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