Comment gérer la distribution des processus mpich

Question

Je courais code mpi sur host1 (quad core) et host2 (dual core)

mpiexec -hosts host1,host2 -n 6 ./mytask 

Je veux attribuer 4 processus pour host1 et 2 pour host2. J'ai essayé --map-par le noyau mais j'ai trouvé que les processus sont distribués 3 pour chacun.

Ceci est la sortie d'aide mpiexec

mpiexec -h 

Usage: ./mpiexec [global opts] [local opts for exec1] [exec1] [exec1 args] : [local opts for exec2] [exec2] [exec2 args] : ... 

Global options (passed to all executables): 

    Global environment options: 
    -genv {name} {value}    environment variable name and value 
    -genvlist {env1,env2,...}  environment variable list to pass 
    -genvnone      do not pass any environment variables 
    -genvall       pass all environment variables not managed 
              by the launcher (default) 

    Other global options: 
    -f {name}      file containing the host names 
    -hosts {host list}    comma separated host list 
    -wdir {dirname}     working directory to use 
    -configfile {name}    config file containing MPMD launch options 


Local options (passed to individual executables): 

    Local environment options: 
    -env {name} {value}    environment variable name and value 
    -envlist {env1,env2,...}   environment variable list to pass 
    -envnone       do not pass any environment variables 
    -envall       pass all environment variables (default) 

    Other local options: 
    -n/-np {value}     number of processes 
    {exec_name} {args}    executable name and arguments 


Hydra specific options (treated as global): 

    Launch options: 
    -launcher      launcher to use (ssh rsh fork slurm ll lsf sge manual persist) 
    -launcher-exec     executable to use to launch processes 
    -enable-x/-disable-x    enable or disable X forwarding 

    Resource management kernel options: 
    -rmk        resource management kernel to use (user slurm ll lsf sge pbs cobalt) 

    Processor topology options: 
    -topolib       processor topology library (hwloc) 
    -bind-to       process binding 
    -map-by       process mapping 
    -membind       memory binding policy 

    Checkpoint/Restart options: 
    -ckpoint-interval    checkpoint interval 
    -ckpoint-prefix     checkpoint file prefix 
    -ckpoint-num      checkpoint number to restart 
    -ckpointlib      checkpointing library (none) 

    Demux engine options: 
    -demux       demux engine (poll select) 

    Other Hydra options: 
    -verbose       verbose mode 
    -info       build information 
    -print-all-exitcodes    print exit codes of all processes 
    -iface       network interface to use 
    -ppn        processes per node 
    -profile       turn on internal profiling 
    -prepend-rank     prepend rank to output 
    -prepend-pattern     prepend pattern to output 
    -outfile-pattern     direct stdout to file 
    -errfile-pattern     direct stderr to file 
    -nameserver      name server information (host:port format) 
    -disable-auto-cleanup   don't cleanup processes on error 
    -disable-hostname-propagation let MPICH auto-detect the hostname 
    -order-nodes      order nodes as ascending/descending cores 
    -localhost      local hostname for the launching node 
    -usize       universe size (SYSTEM, INFINITE, <value>) 

Please see the intructions provided at 
http://wiki.mpich.org/mpich/index.php/Using_the_Hydra_Process_Manager 
for further details 

Answer 1

Il y a plusieurs options.

pi@RPi:~ $ mpiexec -H rpi,rpi,rpi,rpi5,rpi7,rpi7 -np 6 helloworld.py 
Hello World! I am process 3 of 6 on RPi5. 
Hello World! I am process 5 of 6 on RPi7. 
Hello World! I am process 4 of 6 on RPi7. 
Hello World! I am process 0 of 6 on RPi. 
Hello World! I am process 2 of 6 on RPi. 
Hello World! I am process 1 of 6 on RPi. 

Le fichier hôte avec le nom de fichier -hostfile.

pi@RPi:~ $ cat filename 
RPi slots=4 max_slots=4 
RPi5 slots=2 max_slots=2 
RPi7 slots=4 max_slots=4 

Utilisez également l'option -nooversubscribe.