Re: [PATCH 30/31] sched, numa, mm: Implement slow start for workingset sampling

[Mel Gorman]

On Thu, Oct 25, 2012 at 02:16:47PM +0200, Peter Zijlstra wrote:
> Add a 1 second delay before starting to scan the working set of
> a task and starting to balance it amongst nodes.
> 
> [ note that before the constant per task WSS sampling rate patch
>   the initial scan would happen much later still, in effect that
>   patch caused this regression. ]
> 
> The theory is that short-run tasks benefit very little from NUMA
> placement: they come and go, and they better stick to the node
> they were started on. As tasks mature and rebalance to other CPUs
> and nodes, so does their NUMA placement have to change and so
> does it start to matter more and more.
> 

Yeah, ok. It's done by wall time, right? Should it be CPU time in case
it spent the first second asleep?

-- 
Mel Gorman
SUSE Labs
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