Date: Tue, 20 Dec 2011 10:29:55 +0100 From: Gary Jennejohn <gljennjohn@googlemail.com> To: Andriy Gapon <avg@FreeBSD.org> Cc: freebsd-performance@FreeBSD.org, freebsd-current@FreeBSD.org, Nathan Whitehorn <nwhitehorn@FreeBSD.org> Subject: Re: SCHED_ULE should not be the default Message-ID: <20111220102955.068bb756@ernst.jennejohn.org> In-Reply-To: <4EEFAB20.4070300@FreeBSD.org> References: <4EE1EAFE.3070408@m5p.com> <4EE22421.9060707@gmail.com> <4EE6060D.5060201@mail.zedat.fu-berlin.de> <4EE69C5A.3090005@FreeBSD.org> <20111213104048.40f3e3de@nonamehost> <20111213090051.GA3339@vniz.net> <4EED5200.20302@cran.org.uk> <20111218164924.L64681@sola.nimnet.asn.au> <20111218075241.GA45367@vniz.net> <20111218102401.GA42627@freebsd.org> <20111218102600.GA44118@freebsd.org> <CAJ-VmomJ9D63xYyg4udKu1FnihVworgp8MrxzXwpG2XVZww8DA@mail.gmail.com> <4EEF5D5A.5050700@freebsd.org> <4EEFAB20.4070300@FreeBSD.org>
next in thread | previous in thread | raw e-mail | index | archive | help
On Mon, 19 Dec 2011 23:22:40 +0200 Andriy Gapon <avg@FreeBSD.org> 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
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20111220102955.068bb756>