From: Rik van Riel <riel@redhat.com>
To: vatsa@linux.vnet.ibm.com
Cc: Mike Galbraith <efault@gmx.de>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
Avi Kiviti <avi@redhat.com>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
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 12:33:29 -0500 [thread overview]
Message-ID: <4CF929E9.6000603@redhat.com> (raw)
In-Reply-To: <20101203172954.GC11725@linux.vnet.ibm.com>
On 12/03/2010 12:29 PM, Srivatsa Vaddagiri wrote:
> On Fri, Dec 03, 2010 at 12:09:01PM -0500, Rik van Riel wrote:
>> I don't see how that is going to help get the lock
>> released, when the VCPU holding the lock is on another
>> CPU.
>
> Even the directed yield() is not guaranteed to get the lock released, given its
> shooting in the dark?
True, that's a fair point.
> Anyway, the intention of yield() proposed was not to get lock released
> immediately (which will happen eventually), but rather to avoid inefficiency
> associated with (long) spinning and at the same time make sure we are not
> leaking our bandwidth to other guests because of a naive yield ..
A KVM guest can run on the host alongside short-lived
processes, though. How can we ensure that a VCPU that
donates time gets it back again later, when the task
time was donated to may no longer exist?
--
All rights reversed
next prev parent reply other threads:[~2010-12-03 17:33 UTC|newest]
Thread overview: 65+ 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 [this message]
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
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
-- strict thread matches above, loose matches on Subject: below --
2011-01-02 11:43 [RFC PATCH 2/3] sched: add yield_to function Hillf Danton
2011-01-02 17:19 ` Rik van Riel
2011-01-03 4:18 ` Hillf Danton
2011-01-03 5:04 ` Rik van Riel
2011-01-04 12:44 ` Hillf Danton
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