Run a multithreaded job in 1 slot?

Question

What happens if I would try to run a multithreaded job in 1 SGE slot? Would it fail to start multiple threads? Or would it still start these multiple threads and potentially overload the SGE cluster node, because it is going to run more threads than there are slots?

I know I should use the -pe threaded nrThreads parameter. But I am running a program of which I am not sure how many threads it is using for every step.

Answer 1

It's been a while since I've used SGE, but at least back then, a job which launched more computational threads than allocated would not be prevented from launching those threads, usually then stealing CPU time from other jobs.

Perhaps current SGE versions are capable of using cpusets, which allow the administrator to limit the CPU's used by a job. At least the slurm scheduler can do this.