Re: [RFC -v5 PATCH 2/4] sched: Add yield_to(task, preempt)functionality.

From: Srivatsa Vaddagiri
Date: Mon Jan 17 2011 - 10:56:24 EST


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
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