From: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
To: Rik van Riel <riel@redhat.com>
Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
Avi Kiviti <avi@redhat.com>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Mike Galbraith <efault@gmx.de>,
Chris Wright <chrisw@sous-sol.org>,
ttracy@redhat.com, dshaks@redhat.com
Subject: Re: [RFC -v5 PATCH 2/4] sched: Add yield_to(task, preempt) functionality.
Date: Mon, 17 Jan 2011 21:23:16 +0530 [thread overview]
Message-ID: <20110117155315.GA20416@linux.vnet.ibm.com> (raw)
In-Reply-To: <4D309620.60507@redhat.com>
On Fri, Jan 14, 2011 at 01:29:52PM -0500, Rik van Riel wrote:
> >I am not sure whether we are meeting that objective via this patch, as
> >lock-spinning vcpu would simply yield after setting next buddy to preferred
> >vcpu on target pcpu, thereby leaking some amount of bandwidth on the pcpu
> >where it is spinning.
>
> Have you read the patch?
Sorry had mis-read the patch!
On reviewing it further, I am wondering if we can optimize yield_to() further
for case when target and current are on same pcpu, by swapping vruntimes of two
tasks (to let target run in current's place - as we do in task_fork_fair()).
- vatsa
next prev parent reply other threads:[~2011-01-17 15:56 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-01-14 8:02 [RFC -v5 PATCH 0/4] directed yield for Pause Loop Exiting Rik van Riel
2011-01-14 8:03 ` [RFC -v5 PATCH 1/4] kvm: keep track of which task is running a KVM vcpu Rik van Riel
2011-01-16 15:17 ` Avi Kivity
2011-01-14 8:03 ` [RFC -v5 PATCH 2/4] sched: Add yield_to(task, preempt) functionality Rik van Riel
2011-01-14 17:15 ` Peter Zijlstra
2011-01-14 17:47 ` Srivatsa Vaddagiri
2011-01-14 18:29 ` Rik van Riel
2011-01-17 15:53 ` Srivatsa Vaddagiri [this message]
2011-01-14 8:04 ` [RFC -v5 PATCH 3/4] export pid symbols needed for kvm_vcpu_on_spin Rik van Riel
2011-01-16 15:18 ` Avi Kivity
2011-01-14 8:05 ` [RFC -v5 PATCH 4/4] kvm: use yield_to instead of sleep in kvm_vcpu_on_spin Rik van Riel
2011-01-14 17:34 ` [RFC -v5 PATCH 0/4] directed yield for Pause Loop Exiting Rik van Riel
2011-01-14 21:29 ` Rik van Riel
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