Category Archives: Julia

Using julia -L startupfile.jl, rather than machinefiles for starting workers.

If one wants to have full control over the worker process to method to use is addprocs and the -L startupfile.jl commandline arguement when you start julia
See the documentation for addprocs.

The simplest way to add processes to the julia worker is to invoke it with julia -p 4.
The -p 4 argument says start 4 worker processes, on the local machine.
For more control, one uses julia --machinefile ~/machines
Where ~/machines is a file listing the hosts.
The machinefile is often just a list of hostnames/IP-addresses,
but sometimes is more detailed.
Julia will connect to each host and start a number of workers on each equal to the number of cores.

Even the most detailed machinefile doesn’t give full control,
for example you can not specify the topology, or the location of the julia exectuable.

For full control, one shoud invoke addprocs directly,
and to do so, one should use julia -L startupfile.jl

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