Periodic rant about SCHED_ULE
- Reply: Matthias Andree : "Re: Periodic rant about SCHED_ULE"
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Date: Tue, 21 Mar 2023 22:52:16 UTC
Yes, you've all heard it before, but I've just reverified on FreeBSD 13.1-RELEASE-p7 that SCHED_ULE gives terrible performance for "make buildworld" in the presence of a totally compute-bound job (misc/dnetc from ports) running at nice 20. World builds in: 15597 seconds with SCHED_4BSD without dnetc 20477 seconds with SCHED_4BSD with dnetc 16006 seconds with SCHED_ULE without dnetc 50290 seconds with SCHED_ULE with dnetc. When I ask why SCHED_ULE is the default scheduler, I have been told more than once that there is some circumstance in which it gives superior performance. But no one seems to know what circumstance that is. Guess what! I propose that SCHED_4BSD be the default scheduler. -- George