Date: Sun, 8 Oct 2006 17:22:00 -0700 From: John-Mark Gurney <gurney_j@resnet.uoregon.edu> To: Kip Macy <kmacy@fsmware.com> Cc: Attilio Rao <attilio@freebsd.org>, freebsd-current@freebsd.org, David Xu <davidxu@freebsd.org>, Ivan Voras <ivoras@fer.hr> Subject: Re: [PATCH] MAXCPU alterable in kernel config - needs testers Message-ID: <20061009002200.GM793@funkthat.com> In-Reply-To: <20061008155817.G29803@demos.bsdclusters.com> References: <2fd864e0610080423q7ba6bdeal656a223e662a5d@mail.gmail.com> <20061008135031.G83537@demos.bsdclusters.com> <4529667D.8070108@fer.hr> <200610090634.31297.davidxu@freebsd.org> <20061008225150.GK793@funkthat.com> <3bbf2fe10610081555r67265368sf7f12edbf35bff0d@mail.gmail.com> <20061008155817.G29803@demos.bsdclusters.com>
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Kip Macy wrote this message on Sun, Oct 08, 2006 at 15:59 -0700:
> >
> > How would you see a sched_lock decomposition (and, if it is possible,
> > how many locks it could be decomposed in?)
>
> Rather than having a per thread lock, Solaris uses the lock for the
> current container that a thread is associated with (cpu, run queue,
Wouldn't having a single run queue lock still serialize the cpu's when
getting a thread to run? Don't we really need a per cpu run queue, and
then have a scheduler that puts threads on the cpu's run queues?
we probably should move some of the stats (LA) to pcpu data structure
and desolving sched_lock from thread priority updates... This would
mean sched_lock would need to be aquired less often, closer to quantum
(which is ~100ms now) instead of each hz...
There is probably work to be done to push the locks down around
thread, proc and kse/ksg... It looks like a lot of the work done
each HZ could be a lot more local than it currently is... It's
probably not so much scheduling over head that is killing sun4v but
the stats gathering..
Though I have very little knowlege about how scheduling works, so I
am probably incorrect..
--
John-Mark Gurney Voice: +1 415 225 5579
"All that I will do, has been done, All that I have, has not."
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