Assigning cores

Do you have 20 actual cores or 10 cores/20 threads? detectCores() doesn't usually know the difference but the CPU may be too busy accessing memory to let that last thread get any useful work done. I often find that allocating real cores is more practical than thinking in terms of thread so try allocating 9 workers and watch your cpu usage.

Experiment with your settings... the right balance may be dependent on your other activities as well as your hardware, since your analysis may not be completely memory access limited and threads might make (some) sense for you.

Hi all,

I'm working on a large simulation and I'm using the doParallel package
to
parallelize my work. I have 20 cores on my machine and would like to
preserve some for day-to-day activities - word processing, sending
emails,
etc.

I started by saving 1 core and it was clear that *everything* was so
slow
as to be nearly unusable.

Any suggestions on how many cores to hold back (e.g., not to put to
work on
the parallel process)?

Thanks,
Leslie

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