From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: vatsa@linux.vnet.ibm.com
Cc: Rik van Riel <riel@redhat.com>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
Avi Kiviti <avi@redhat.com>, Ingo Molnar <mingo@elte.hu>,
Anthony Liguori <aliguori@linux.vnet.ibm.com>
Subject: Re: [RFC PATCH 2/3] sched: add yield_to function
Date: Fri, 03 Dec 2010 15:03:30 +0100 [thread overview]
Message-ID: <1291385010.32004.2165.camel@laptop> (raw)
In-Reply-To: <20101203133056.GF27994@linux.vnet.ibm.com>
On Fri, 2010-12-03 at 19:00 +0530, Srivatsa Vaddagiri wrote:
> On Fri, Dec 03, 2010 at 02:23:39PM +0100, Peter Zijlstra wrote:
> > Right, so another approach might be to simply swap the vruntime between
> > curr and p.
>
> Can't that cause others to stave? For ex: consider a cpu p0 having these tasks:
>
> p0 -> A0 B0 A1
>
> A0/A1 have entered some sort of AB<->BA spin-deadlock, as a result A0 wants to
> direct yield to A1 which wants to direct yield to A0. If we keep swapping their
> runtimes, can't it starve B0?
No, because they do receive service (they spend some time spinning
before being interrupted), so the respective vruntimes will increase, at
some point they'll pass B0 and it'll get scheduled.
next prev parent reply other threads:[~2010-12-03 14:03 UTC|newest]
Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-12-02 19:41 [RFC PATCH 0/3] directed yield for Pause Loop Exiting Rik van Riel
2010-12-02 19:43 ` [RFC PATCH 1/3] kvm: keep track of which task is running a KVM vcpu Rik van Riel
2010-12-03 1:18 ` Chris Wright
2010-12-03 14:50 ` Rik van Riel
2010-12-03 15:55 ` Chris Wright
2010-12-05 12:40 ` Avi Kivity
2010-12-03 12:17 ` Srivatsa Vaddagiri
2010-12-03 14:16 ` Rik van Riel
2010-12-05 12:59 ` Avi Kivity
2010-12-02 19:44 ` [RFC PATCH 2/3] sched: add yield_to function Rik van Riel
2010-12-03 0:50 ` Chris Wright
2010-12-03 18:27 ` Rik van Riel
2010-12-03 19:30 ` Chris Wright
2010-12-03 21:30 ` Peter Zijlstra
2010-12-03 5:54 ` Mike Galbraith
2010-12-03 13:46 ` Srivatsa Vaddagiri
2010-12-03 14:45 ` Mike Galbraith
2010-12-03 14:48 ` Rik van Riel
2010-12-03 15:09 ` Mike Galbraith
2010-12-03 15:35 ` Rik van Riel
2010-12-03 16:20 ` Srivatsa Vaddagiri
2010-12-03 17:09 ` Rik van Riel
2010-12-03 17:29 ` Srivatsa Vaddagiri
2010-12-03 17:33 ` Rik van Riel
2010-12-03 17:45 ` Srivatsa Vaddagiri
2010-12-03 20:05 ` Mike Galbraith
2010-12-03 21:26 ` Peter Zijlstra
2010-12-03 13:23 ` Peter Zijlstra
2010-12-03 13:30 ` Srivatsa Vaddagiri
2010-12-03 14:03 ` Peter Zijlstra [this message]
2010-12-03 14:06 ` Srivatsa Vaddagiri
2010-12-03 14:10 ` Srivatsa Vaddagiri
2010-12-03 21:23 ` Peter Zijlstra
2010-12-04 13:02 ` Rik van Riel
2010-12-10 4:34 ` Rik van Riel
2010-12-10 8:39 ` Srivatsa Vaddagiri
2010-12-10 14:55 ` Rik van Riel
2010-12-08 17:55 ` Rik van Riel
2010-12-08 20:00 ` Peter Zijlstra
2010-12-08 20:04 ` Peter Zijlstra
2010-12-08 22:59 ` Rik van Riel
2010-12-02 19:45 ` [RFC PATCH 3/3] kvm: use yield_to instead of sleep in kvm_vcpu_on_spin Rik van Riel
2010-12-03 2:24 ` Chris Wright
2010-12-05 12:58 ` Avi Kivity
2010-12-05 12:56 ` Avi Kivity
2010-12-08 22:38 ` Rik van Riel
2010-12-09 10:28 ` Avi Kivity
2010-12-09 17:07 ` Rik van Riel
2010-12-11 7:27 ` Avi Kivity
2010-12-02 22:41 ` [RFC PATCH 0/3] directed yield for Pause Loop Exiting Chris Wright
2010-12-05 13:02 ` Avi Kivity
2010-12-10 5:03 ` Balbir Singh
2010-12-10 14:54 ` Rik van Riel
2010-12-11 7:31 ` Avi Kivity
2010-12-11 13:57 ` Balbir Singh
2010-12-13 11:57 ` Avi Kivity
2010-12-13 12:39 ` Balbir Singh
2010-12-13 12:42 ` Avi Kivity
2010-12-13 17:02 ` Rik van Riel
2010-12-14 9:25 ` Balbir Singh
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