From: Peter Zijlstra <peterz@infradead.org>
To: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>, James Hartsock <hartsjc@redhat.com>,
Rik van Riel <riel@redhat.com>,
Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>,
Kirill Tkhai <ktkhai@parallels.com>,
linux-kernel@vger.kernel.org
Subject: Re: [RFC] sched: unused cpu in affine workload
Date: Mon, 4 Apr 2016 15:23:21 +0200 [thread overview]
Message-ID: <20160404132321.GZ3448@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <20160404093844.GA16017@gmail.com>
On Mon, Apr 04, 2016 at 11:38:44AM +0200, Ingo Molnar wrote:
> We'd upgrade that to O(nr_cpus^2), which is totally unrealistic with 16,000 CPUs
> even in a slowpath - but it would probably cause problems even with 120 CPUs. It
> will get quadratically worse as the number of CPUs in a system increases on its
> current exponential trajectory ...
The arbitrary affinity thing is I think a packing problem, which is NP
hard IIRC.
next prev parent reply other threads:[~2016-04-04 13:23 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-04 8:23 Jiri Olsa
2016-04-04 8:44 ` Peter Zijlstra
2016-04-04 8:59 ` Ingo Molnar
2016-04-04 9:19 ` Ingo Molnar
2016-04-04 9:38 ` Ingo Molnar
2016-04-04 13:23 ` Peter Zijlstra [this message]
2016-04-04 19:45 ` Rik van Riel
2016-04-04 21:34 ` Peter Zijlstra
2016-04-05 8:56 ` Jiri Olsa
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