Parallel with Julia

Overview

Teaching: 5 min min
Exercises: 0 min

Questions

• How to run parallel with Julia in Palmetto

Objectives

1. Request compute node with multiple cores:

qsub -I -l select=1:ncpus=16:mem=32gb:interconnect=any,walltime=4:00:00

1. Load the Julia module:

$ module load julia/1.4.0-gcc/8.3.1

1. Set the environment variable JULIA_NUM_THREADS to the number of requested CPUs:

$ export JULIA_NUM_THREADS=8

1. Start Julia with -p option to specify the number of workers:

julia -p 8

1. Within Julia, load the Distributed package:

julia> using Distributed

1. Double check that the number of threads is set properly:

julia> println(Threads.nthreads())

1. You can use this option with ps:

ps -p <pid> -L -o pid,tid,psr,pcpu

where is the process ID which you can get from top or from ps -u .

Key Points

• parallel, julia