Re: SCHED_ULE should not be the default
Gary Jennejohn <[email protected]>
| Newsgroups | gmane.os.freebsd.current,gmane.os.freebsd.performance |
|---|---|
| Message-ID | <[email protected]> |
On Mon, 19 Dec 2011 23:22:40 +0200 Andriy Gapon <[email protected]> wrote: > on 19/12/2011 17:50 Nathan Whitehorn said the following: > > The thing I've seen is that ULE is substantially more enthusiastic about > > migrating processes between cores than 4BSD. > > Hmm, this seems to be contrary to my theoretical expectations. I thought that > with 4BSD all threads that were not in one of the following categories: > - temporary pinned > - bound to cpu in kernel via sched_bind > - belong to a cpu set which a strict subset of a total set > were placed onto a common queue that was shared by all cpus. And as such I > expected them to get picked up by the cpus semi-randomly. > > In other words, I thought that it was ULE that took into account cpu/cache > affinities while 4BSD was deliberately entirely ignorant of those details. > I have a 6-core AMD CPU running FreeeBSD 10.0 and SCHED_4BSD. I've noticed with large ports builds which are not MAKE_JOBS_SAFE that the compile load migrates between the cores pretty quickly, but I haven't compared it to ULE. -- Gary Jennejohn _______________________________________________ [email protected] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-current To unsubscribe, send any mail to "[email protected]"