Date: Sun, 20 Jan 2008 11:13:16 -0800 From: Jeremy Chadwick <koitsu@FreeBSD.org> To: TooMany Secrets <toomany@toomany.net> Cc: "Jason C. Wells" <jcw@highperformance.net>, freebsd-stable <freebsd-stable@freebsd.org> Subject: Re: Scheduler in Various Docs Message-ID: <20080120191316.GA13382@eos.sc1.parodius.com> In-Reply-To: <e8b5dfd50801201040s755d7dc4p962095d63b57503a@mail.gmail.com> References: <479388C0.50507@highperformance.net> <47938F21.6020308@math.missouri.edu> <e8b5dfd50801201040s755d7dc4p962095d63b57503a@mail.gmail.com>
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On Sun, Jan 20, 2008 at 07:40:07PM +0100, TooMany Secrets wrote: > On 1/20/08, Stephen Montgomery-Smith <stephen@math.missouri.edu> wrote: > > Jason C. Wells wrote: > > > The comments regarding SCHED_ULE and SCHED_4BSD are inconsistent with > > > information found in the email archives. LINT says ULE is experimental. > > > The handbook doesn't mention ULE at all. The archives say ULE is the > > > new recommended scheduler. > > > > > > If ULE is in fact the current recommendation, then a few docs need to be > > > updated. > > > > To add to Jason's point - why does GENERIC still default to SCHED_4BSD? > > Are there plans to change this before 7.0 is truly released? > > Excuse me for my bad english... > > This question was mentioned two or three months ago. The answer was > that in 7.1, after the ULE will be tested in 7.0, it will be the > defacto scheduler in FreeBSD. First, the scheduler need the best > benchark in the world; a few thousand users testing in real-life > situations on a daily basis. This is correct. There was a very large discussion on freebsd-current (which would've been discussing 7.x at that point) about what scheduler should be the default for RELENG_7 (4BSD or the "new" ULE (a.k.a. SMP2)). It was ""voted"" (note the quotes) that SCHED_4BSD should remain the default until 7.1 was released, since if there turned out to be a gigantic bug in the new scheduler, we wouldn't want people to get bit by it (thus harming the stability reputation of -RELEASE and -STABLE). The 4BSD scheduler is still considered stable and has a track record to prove it. In a way, SCHED_ULE on 7.x is still considered "experimental" in the sense that it needs lots of people testing it. So far all the results have been positive (unlike SCHED_ULE on 6.x and 5.x, which were very broken -- hence the rewrite!). If the OP wants to read the thread/discussion (it's long), I can dig up a URL to it in the archives. -- | Jeremy Chadwick jdc at parodius.com | | Parodius Networking http://www.parodius.com/ | | UNIX Systems Administrator Mountain View, CA, USA | | Making life hard for others since 1977. PGP: 4BD6C0CB |
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