From: Chris Wright <chrisw@sous-sol.org>
To: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Chris Wright <chrisw@sous-sol.org>,
vatsa@linux.vnet.ibm.com, Avi Kivity <avi@redhat.com>,
Anthony Liguori <aliguori@linux.vnet.ibm.com>,
qemu-devel@nongnu.org, kvm@vger.kernel.org,
Ingo Molnar <mingo@elte.hu>, Mike Galbraith <efault@gmx.de>,
riel@redhat.com
Subject: Re: [PATCH] qemu-kvm: response to SIGUSR1 to start/stop a VCPU (v2)
Date: Wed, 1 Dec 2010 09:46:56 -0800 [thread overview]
Message-ID: <20101201174656.GC8514@sequoia.sous-sol.org> (raw)
In-Reply-To: <1291224176.32004.1763.camel@laptop>
* Peter Zijlstra (a.p.zijlstra@chello.nl) wrote:
> On Wed, 2010-12-01 at 09:17 -0800, Chris Wright wrote:
> > Directed yield and fairness don't mix well either. You can end up
> > feeding the other tasks more time than you'll ever get back.
>
> If the directed yield is always to another task in your cgroup then
> inter-guest scheduling fairness should be maintained.
>
> Yes, but not the inter-vcpu fairness.
That same vcpu doesn't get fair scheduling if it spends its entire
timeslice spinning on a lock held by a de-scheduled vcpu.
WARNING: multiple messages have this Message-ID (diff)
From: Chris Wright <chrisw@sous-sol.org>
To: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: kvm@vger.kernel.org, Mike Galbraith <efault@gmx.de>,
qemu-devel@nongnu.org, vatsa@linux.vnet.ibm.com,
Chris Wright <chrisw@sous-sol.org>,
Anthony Liguori <aliguori@linux.vnet.ibm.com>,
Avi Kivity <avi@redhat.com>
Subject: [Qemu-devel] Re: [PATCH] qemu-kvm: response to SIGUSR1 to start/stop a VCPU (v2)
Date: Wed, 1 Dec 2010 09:46:56 -0800 [thread overview]
Message-ID: <20101201174656.GC8514@sequoia.sous-sol.org> (raw)
In-Reply-To: <1291224176.32004.1763.camel@laptop>
* Peter Zijlstra (a.p.zijlstra@chello.nl) wrote:
> On Wed, 2010-12-01 at 09:17 -0800, Chris Wright wrote:
> > Directed yield and fairness don't mix well either. You can end up
> > feeding the other tasks more time than you'll ever get back.
>
> If the directed yield is always to another task in your cgroup then
> inter-guest scheduling fairness should be maintained.
>
> Yes, but not the inter-vcpu fairness.
That same vcpu doesn't get fair scheduling if it spends its entire
timeslice spinning on a lock held by a de-scheduled vcpu.
next prev parent reply other threads:[~2010-12-01 17:47 UTC|newest]
Thread overview: 80+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-11-23 16:49 [PATCH] qemu-kvm: response to SIGUSR1 to start/stop a VCPU (v2) Anthony Liguori
2010-11-23 16:49 ` [Qemu-devel] " Anthony Liguori
2010-11-23 19:35 ` Blue Swirl
2010-11-23 19:35 ` Blue Swirl
2010-11-23 21:46 ` Anthony Liguori
2010-11-23 21:46 ` Anthony Liguori
2010-11-23 23:43 ` Paolo Bonzini
2010-11-23 23:43 ` Paolo Bonzini
2010-11-24 1:15 ` Anthony Liguori
2010-11-24 1:15 ` Anthony Liguori
2010-11-24 2:08 ` Paolo Bonzini
2010-11-24 2:08 ` Paolo Bonzini
2010-11-24 8:18 ` Avi Kivity
2010-11-24 8:18 ` [Qemu-devel] " Avi Kivity
2010-11-24 13:58 ` Anthony Liguori
2010-11-24 13:58 ` [Qemu-devel] " Anthony Liguori
2010-11-24 14:23 ` Avi Kivity
2010-11-24 14:23 ` [Qemu-devel] " Avi Kivity
2010-12-01 12:37 ` Srivatsa Vaddagiri
2010-12-01 12:37 ` [Qemu-devel] " Srivatsa Vaddagiri
2010-12-01 12:56 ` Avi Kivity
2010-12-01 12:56 ` [Qemu-devel] " Avi Kivity
2010-12-01 16:12 ` Srivatsa Vaddagiri
2010-12-01 16:12 ` [Qemu-devel] " Srivatsa Vaddagiri
2010-12-01 16:25 ` Peter Zijlstra
2010-12-01 16:25 ` [Qemu-devel] " Peter Zijlstra
2010-12-01 17:17 ` Chris Wright
2010-12-01 17:17 ` [Qemu-devel] " Chris Wright
2010-12-01 17:22 ` Peter Zijlstra
2010-12-01 17:22 ` [Qemu-devel] " Peter Zijlstra
2010-12-01 17:26 ` Rik van Riel
2010-12-01 17:26 ` [Qemu-devel] " Rik van Riel
2010-12-01 19:07 ` Peter Zijlstra
2010-12-01 19:07 ` [Qemu-devel] " Peter Zijlstra
2010-12-01 19:24 ` Rik van Riel
2010-12-01 19:24 ` [Qemu-devel] " Rik van Riel
2010-12-01 19:35 ` Peter Zijlstra
2010-12-01 19:35 ` [Qemu-devel] " Peter Zijlstra
2010-12-01 19:42 ` Rik van Riel
2010-12-01 19:42 ` [Qemu-devel] " Rik van Riel
2010-12-01 19:47 ` Peter Zijlstra
2010-12-01 19:47 ` [Qemu-devel] " Peter Zijlstra
2010-12-02 9:07 ` Avi Kivity
2010-12-02 9:07 ` [Qemu-devel] " Avi Kivity
2010-12-01 17:46 ` Chris Wright [this message]
2010-12-01 17:46 ` Chris Wright
2010-12-01 17:29 ` Srivatsa Vaddagiri
2010-12-01 17:29 ` [Qemu-devel] " Srivatsa Vaddagiri
2010-12-01 17:45 ` Peter Zijlstra
2010-12-01 17:45 ` [Qemu-devel] " Peter Zijlstra
2010-12-01 18:00 ` Srivatsa Vaddagiri
2010-12-01 18:00 ` [Qemu-devel] " Srivatsa Vaddagiri
2010-12-01 19:09 ` Peter Zijlstra
2010-12-01 19:09 ` [Qemu-devel] " Peter Zijlstra
2010-12-02 9:17 ` Avi Kivity
2010-12-02 9:17 ` [Qemu-devel] " Avi Kivity
2010-12-02 11:47 ` Srivatsa Vaddagiri
2010-12-02 11:47 ` [Qemu-devel] " Srivatsa Vaddagiri
2010-12-02 12:22 ` Srivatsa Vaddagiri
2010-12-02 12:22 ` [Qemu-devel] " Srivatsa Vaddagiri
2010-12-02 12:41 ` Avi Kivity
2010-12-02 12:41 ` [Qemu-devel] " Avi Kivity
2010-12-02 13:13 ` Srivatsa Vaddagiri
2010-12-02 13:13 ` [Qemu-devel] " Srivatsa Vaddagiri
2010-12-02 13:49 ` Avi Kivity
2010-12-02 13:49 ` [Qemu-devel] " Avi Kivity
2010-12-02 15:27 ` Srivatsa Vaddagiri
2010-12-02 15:27 ` [Qemu-devel] " Srivatsa Vaddagiri
2010-12-02 15:28 ` Srivatsa Vaddagiri
2010-12-02 15:28 ` [Qemu-devel] " Srivatsa Vaddagiri
2010-12-02 15:33 ` Avi Kivity
2010-12-02 15:33 ` [Qemu-devel] " Avi Kivity
2010-12-02 15:44 ` Srivatsa Vaddagiri
2010-12-02 15:44 ` [Qemu-devel] " Srivatsa Vaddagiri
2010-12-02 12:19 ` Srivatsa Vaddagiri
2010-12-02 12:19 ` [Qemu-devel] " Srivatsa Vaddagiri
2010-12-02 12:42 ` Avi Kivity
2010-12-02 12:42 ` [Qemu-devel] " Avi Kivity
2010-12-02 9:14 ` Avi Kivity
2010-12-02 9:14 ` [Qemu-devel] " Avi Kivity
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