From: Peter Zijlstra <peterz@infradead.org>
To: Rolando Martins <rolando.martins@gmail.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: cgroup, RT reservation per core(s)?
Date: Tue, 10 Feb 2009 17:00:02 +0100 [thread overview]
Message-ID: <1234281602.23438.96.camel@twins> (raw)
In-Reply-To: <b6a2d2e20902100646q6c7073cse86b8f5790a120ac@mail.gmail.com>
On Tue, 2009-02-10 at 14:46 +0000, Rolando Martins wrote:
>
> > I've never actually tried anything like this, let me know if it
> > works ;-)
> >
>
> Thanks Peter, it works!
> I am thinking for different strategies to be used in my rt middleware
> project, and I think there is a limitation.
> If I wanted to have some RT on the B cpuset, I couldn't because I
> assigned A.cpu.rt_runtime_ns = root.cpu.rt_runtime_ns (then subdivided
> the A cpuset, with 2,3,4, each one having A.cpu.rt_runtime_ns/3).
Try it, you can run RT proglets in B.
You get n*utilization per schedule domain, where n is the number of cpus
in it.
So you still have 200% left in B, even if you use 200% of A.
> This happens because there is a
> global /proc/sys/kernel/sched_rt_runtime_us and
> /proc/sys/kernel/sched_rt_period_us.
These globals don't actually do much (except provide a global cap) in
the cgroup case.
> What do you think about adding a separate tuple (runtime,period) for
> each core/cpu?
> Does this make sense? ;)
That's going to give me a horrible head-ache trying to load-balance
stuff.
next prev parent reply other threads:[~2009-02-10 15:58 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-02-09 19:30 cgroup, RT reservation per core(s)? Rolando Martins
2009-02-09 19:52 ` Peter Zijlstra
2009-02-09 20:04 ` Rolando Martins
2009-02-10 13:06 ` Peter Zijlstra
2009-02-10 14:46 ` Rolando Martins
2009-02-10 16:00 ` Peter Zijlstra [this message]
2009-02-10 17:32 ` Rolando Martins
2009-02-10 19:53 ` Peter Zijlstra
2009-02-11 11:33 ` Rolando Martins
2009-02-11 11:42 ` Peter Zijlstra
2009-02-11 11:53 ` Balbir Singh
2009-02-11 12:00 ` Peter Zijlstra
2009-02-11 12:10 ` Rolando Martins
2009-03-03 12:58 ` Rolando Martins
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