I wrote: >To briefly summarize the previous post related to perf. degradation when >running a >recent kernel... >- kernel build running 1yr old kernel took 100minutes >- same kernel build running recent kernel 148minutes >(ie. Almost a 50% degradation.) >As noted in the last post, I got rid of most of the degradation by disabling >SMP. > >- same kernel build running recent kernel with SCHED_4BSD 104minutes > After poking at this some more, it appears that r312426 is the main cause of this degradation. Doing SMP enabled test runs using SCHED_ULE running the recent kernel, I got: - recent kernel (as above) 148minutes - with r312426 reverted 122minutes - with the "obvious change" mentioned in r312426's commit message, using (flags & SW_TYPE_MASK) == SWT_RELINQUISH instead of (flag & SWT_RELINQUISH) 121minutes
So, I'd say either reverting the patch or replacing it with the "obvious change" mentioned in the commit message will at least mostly fix the problem. I actually suspect that setting "preempt" for SWT_IDLE and/or SWT_IWAIT is what is needed to be the pre-r312426 performance, since those are the ones that SWT_RELINQUISH doesn't match. (There is also SWT_PREEMPT, but that was handled by the r312426 patch.) I also tested: ((flags & SW_PREEMPT) != 0 || (flags & SW_TYPE_MASK) == SWT_IDLE || (flags & SW_TYPE_MASK) == SWT_IWAIT) and it also resulted in 121minutes I still get better perf. from SCHED_4BSD of 104minutes, but I usually see better performance for SCHED_4BSD, so I think this is expected. I know nothing about SCHED_ULE, so I don't think I can do more, unless someone wants me to try a different patch? rick _______________________________________________ firstname.lastname@example.org mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-current To unsubscribe, send any mail to "freebsd-current-unsubscr...@freebsd.org"