I decided to start a new thread on current related to SCHED_ULE, since I see more than just performance degradation and on a recent current kernel. (I cc'd a couple of the people discussing performance problems in freebsd-stable recently under a subject line of "Re: kern.sched.quantum: Creepy, sadistic scheduler".
When testing a pNFS server on a single core i386 with 256Mbytes using a Dec. 2017 current/head kernel, I would see about a 30% performance degradation (elapsed run time for a kernel build over NFSv4.1) when the server kernel was built with options SCHED_ULE instead of options SCHED_4BSD Now, with a kernel from a couple of days ago, the options SCHED_ULE kernel becomes unusable shortly after starting testing. I have seen two variants of this: - Became essentially hung. All I could do was ping the machine from the network. - Reported "vm_thread_new: kstack allocation failed and then any attempt to do anything gets "No more processes". with the only difference being a kernel built with options SCHED_4BSD everything works and performs the same as the Dec 2017 kernel. I can try rolling back through the revisions, but it would be nice if someone could suggest where to start, because it takes a couple of hours to build a kernel on this system. So, something has made things worse for a head/current kernel this winter, rick _______________________________________________ freebsd-current@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-current To unsubscribe, send any mail to "freebsd-current-unsubscr...@freebsd.org"
