[gmx-users] Slow Runs

Justin A. Lemkul jalemkul at vt.edu
Fri Jan 28 21:32:02 CET 2011



Denny Frost wrote:
> Here's my grompp command:
> 
> grompp_d -nice 0 -v -f md.mdp -c ReadyForMD.gro -o md.tpr -p top.top
> 
> and my mdrun command is this: 
> 
> time mpiexec mdrun_mpi -np 8 -cpt 30000 -nice 0 -nt 1 -s 
> $PBS_O_WORKDIR/md.tpr -o $PBS_O_WORKDIR/mdDone.trr -x 
> $PBS_O_WORKDIR/mdDone.xtc -c $PBS_O_WORKDIR/mdDone.gro -e 
> $PBS_O_WORKDIR/md.edr -g $PBS_O_WORKDIR/md.log 1> $PBS_JOBID.pgm.out 4> 
> $PBS_JOBID.pgm.err
> 

The -np option of mdrun is nonexistent, but mdrun does not check for proper 
command line arguments, so you won't get an error.  But then you've said that 8 
processors are active, so I still suspect that mdrun was compiled incorrectly or 
in such a way that it's incompatible with your system.  The output from the .log 
file indicates that only one processor was used.  Maybe your admins can help you 
on this one, if the jobs spit out any useful diagnostic information.

For our cluster, we use e.g.:

mpirun -np 8 mdrun_mpi -deffnm md

-Justin

> I know the -cpt option is 30000 because I don't want a checkpoint file 
> because every time it tries to make it, it fails due to quota issues and 
> kills the job.  I'm not sure why this happens, but I think it's a 
> separate issue to take up with my supercomputing facility.
> 
> On Fri, Jan 28, 2011 at 1:18 PM, Justin A. Lemkul <jalemkul at vt.edu 
> <mailto:jalemkul at vt.edu>> wrote:
> 
> 
> 
>     Denny Frost wrote:
> 
>         all 8 nodes are running at full capacity, though
> 
> 
>     What is your mdrun command line?  How did you compile it?  What can
>     happen is something went wrong during installation, so you think you
>     have an MPI-enabled binary, but it is simply executing 8 copies of
>     the same job.
> 
>     -Justin
> 
>         On Fri, Jan 28, 2011 at 1:13 PM, Justin A. Lemkul
>         <jalemkul at vt.edu <mailto:jalemkul at vt.edu>
>         <mailto:jalemkul at vt.edu <mailto:jalemkul at vt.edu>>> wrote:
> 
> 
> 
>            Denny Frost wrote:
> 
>                Here's what I've got:
> 
>                M E G A - F L O P S   A C C O U N T I N G
> 
>                  RF=Reaction-Field  FE=Free Energy  SCFE=Soft-Core/Free
>         Energy
>                  T=Tabulated        W3=SPC/TIP3p    W4=TIP4p (single or
>         pairs)
>                  NF=No Forces
> 
>                 Computing:                               M-Number      
>                  M-Flops  % Flops
>              
>          -----------------------------------------------------------------------------
>                 Coul(T) + VdW(T)                   1219164.751609      
>             82903203.109    80.6
>                 Outer nonbonded loop                 25980.879385      
>               259808.794     0.3
>                 Calc Weights                         37138.271040      
>              1336977.757     1.3
>                 Spread Q Bspline                    792283.115520      
>              1584566.231     1.5
>                 Gather F Bspline                    792283.115520      
>              4753698.693     4.6
>                 3D-FFT                              119163.856212      
>               953310.850     0.9
>                 Solve PME                             2527.465668      
>               161757.803     0.2
>                 NS-Pairs                             47774.705001      
>              1003268.805     1.0
>                 Reset In Box                           371.386080      
>                 1114.158     0.0
>                 Shift-X                              24758.847360      
>               148553.084     0.1
>                 CG-CoM                                1237.953600      
>                 3713.861     0.0
>                 Angles                               18569.135520      
>              3119614.767     3.0
>                 Propers                              14855.308416      
>              3401865.627     3.3
>                 Impropers                             3094.855920      
>               643730.031     0.6
>                 Virial                                1242.417375      
>                22363.513     0.0
>                 Stop-CM                               1237.953600      
>                12379.536     0.0
>                 P-Coupling                           12379.423680      
>                74276.542     0.1
>                 Calc-Ekin                            12379.436160      
>               334244.776     0.3
>                 Lincs                                11760.476208      
>               705628.572     0.7
>                 Lincs-Mat                           245113.083072      
>               980452.332     1.0
>                 Constraint-V                         23520.928704      
>               188167.430     0.2
>                 Constraint-Vir                       11760.452496      
>               282250.860     0.3
>              
>          -----------------------------------------------------------------------------
>                 Total                                                  
>            102874947.133   100.0
>              
>          -----------------------------------------------------------------------------
> 
> 
>                    R E A L   C Y C L E   A N D   T I M E   A C C O U N T
>         I N G
> 
>                 Computing:         Nodes     Number     G-Cycles  
>          Seconds     %
>              
>          -----------------------------------------------------------------------
>                 Neighbor search    1      99195     8779.027     3300.3
>               3.8
>                 Force                   1     991941   188562.885  
>          70886.8           81.7
>                 PME mesh           1     991941    18012.830     6771.6
>              7.8
>                 Write traj.             1            41     16.835      
>            6.3
>                         0.0
>                 Update                 1     991941     2272.379    
>          854.3              1.0
>                 Constraints           1     991941    11121.146    
>         4180.8     4.8
>                 Rest                     1                    2162.628  
>                   813.0      0.9
>              
>          -----------------------------------------------------------------------
>                 Total                    1                  230927.730  
>                 86813.1   100.0
>              
>          -----------------------------------------------------------------------
>              
>          -----------------------------------------------------------------------
>                 PME spread/gather      1    1983882      17065.384  
>          6415.4   7.4
>                 PME 3D-FFT               1    1983882      503.340      
>         189.2
>                    0.2
>                 PME solve                  1     991941       427.136  
>                    160.6     0.2
>              
>          -----------------------------------------------------------------------
> 
>                Does that mean it's only using 1 node?  That would
>         explain the
>                speed issues.
> 
> 
>            That's what it looks like to me.
> 
> 
>            -Justin
> 
>            --     ========================================
> 
>            Justin A. Lemkul
>            Ph.D. Candidate
>            ICTAS Doctoral Scholar
>            MILES-IGERT Trainee
>            Department of Biochemistry
>            Virginia Tech
>            Blacksburg, VA
>            jalemkul[at]vt.edu <http://vt.edu> <http://vt.edu> | (540)
>         231-9080
> 
>            http://www.bevanlab.biochem.vt.edu/Pages/Personal/justin
> 
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> 
>     -- 
>     ========================================
> 
>     Justin A. Lemkul
>     Ph.D. Candidate
>     ICTAS Doctoral Scholar
>     MILES-IGERT Trainee
>     Department of Biochemistry
>     Virginia Tech
>     Blacksburg, VA
>     jalemkul[at]vt.edu <http://vt.edu> | (540) 231-9080
>     http://www.bevanlab.biochem.vt.edu/Pages/Personal/justin
> 
>     ========================================
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-- 
========================================

Justin A. Lemkul
Ph.D. Candidate
ICTAS Doctoral Scholar
MILES-IGERT Trainee
Department of Biochemistry
Virginia Tech
Blacksburg, VA
jalemkul[at]vt.edu | (540) 231-9080
http://www.bevanlab.biochem.vt.edu/Pages/Personal/justin

========================================



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