Date: Sat, 9 Jun 2018 05:36:55 -0700 (PDT) From: "Rodney W. Grimes" <freebsd-rwg@pdx.rh.CN85.dnsmgr.net> To: gljennjohn@gmail.com Cc: Andriy Gapon <avg@freebsd.org>, FreeBSD Current <freebsd-current@freebsd.org> Subject: Re: Is kern.sched.preempt_thresh=0 a sensible default? Message-ID: <201806091236.w59CatKw019020@pdx.rh.CN85.dnsmgr.net> In-Reply-To: <20180608164033.5ff948f9@ernst.home>
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> On Fri, 8 Jun 2018 17:18:43 +0300 > Andriy Gapon <avg@FreeBSD.org> wrote: > > > On 08/06/2018 15:27, Gary Jennejohn wrote: > > > On Thu, 7 Jun 2018 20:14:10 +0300 > > > Andriy Gapon <avg@FreeBSD.org> wrote: > > > > > >> On 03/05/2018 12:41, Andriy Gapon wrote: > > >>> I think that we need preemption policies that might not be expressible as one or > > >>> two numbers. A policy could be something like this: > > >>> - interrupt threads can preempt only threads from "lower" classes: real-time, > > >>> kernel, timeshare, idle; > > >>> - interrupt threads cannot preempt other interrupt threads > > >>> - real-time threads can preempt other real-time threads and threads from "lower" > > >>> classes: kernel, timeshare, idle > > >>> - kernel threads can preempt only threads from lower classes: timeshare, idle > > >>> - interactive timeshare threads can only preempt batch and idle threads > > >>> - batch threads can only preempt idle threads > > >> > > >> > > >> Here is a sketch of the idea: https://reviews.freebsd.org/D15693 > > >> > > > > > > What about SCHED_4BSD? Or is this just an example and you chose > > > SCHED_ULE for it? > > > > I haven't looked at SCHED_4BSD code at all. > > > > I hope you will eventually because that's what I use. I find its > scheduling of interactive processes much better than ULE. +1 Bruce Evans may have some info and/or changes here too. -- Rod Grimes rgrimes@freebsd.org
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