Re: [PATCH v5 8/9] KVM-GST: adjust scheduler cpu power

[Eric B Munson]

On Mon, 04 Jul 2011, Glauber Costa wrote:

> This patch makes update_rq_clock() aware of steal time.
> The mechanism of operation is not different from irq_time,
> and follows the same principles. This lives in a CONFIG
> option itself, and can be compiled out independently of
> the rest of steal time reporting. The effect of disabling it
> is that the scheduler will still report steal time (that cannot be
> disabled), but won't use this information for cpu power adjustments.
> 
> Everytime update_rq_clock_task() is invoked, we query information
> about how much time was stolen since last call, and feed it into
> sched_rt_avg_update().
> 
> Although steal time reporting in account_process_tick() keeps
> track of the last time we read the steal clock, in prev_steal_time,
> this patch do it independently using another field,
> prev_steal_time_rq. This is because otherwise, information about time
> accounted in update_process_tick() would never reach us in update_rq_clock().
> 
> Signed-off-by: Glauber Costa <glommer@xxxxxxxxxx>
> CC: Rik van Riel <riel@xxxxxxxxxx>
> CC: Jeremy Fitzhardinge <jeremy.fitzhardinge@xxxxxxxxxx>
> CC: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> CC: Avi Kivity <avi@xxxxxxxxxx>
> CC: Anthony Liguori <aliguori@xxxxxxxxxx>
> CC: Eric B Munson <emunson@xxxxxxxxx>

Tested-by: Eric B Munson <emunson@xxxxxxxxx>

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