Ole pointed out this has first class support as documented in the manpage, and -P procfile works for me as advertised.
--jobs procfile -j procfile --max-procs procfile -P procfile Read parameter from file. Use the content of procfile as parameter for -j. E.g. procfile could contain the string 100% or +2 or 10. If procfile is changed when a job completes, procfile is read again and the new number of jobs is computed. If the number is lower than before, running jobs will be allowed to finish but new jobs will not be started until the wanted number of jobs has been reached. This makes it possible to change the number of simultaneous running jobs while GNU parallel is running. > On Jan 21, 2021, at 6:04 PM, Joe Sapp <sa...@ieee.org> wrote: > > You could use an sshloginfile with just the localhost and the number of > processes. Something like this in the file: > 4/: > > Then change the number in the file and you'll change the number of jobs next > time a job is finished. -- Stuart Anderson s...@caltech.edu