Re: [PATCH v5 3/7] sched: set initial value of runnable avg for newforked task

[Alex Shi]

On 05/08/2013 07:34 PM, Peter Zijlstra wrote:
>> > If we wanted to be more exacting about it we could just give them a
>> > sched_slice() worth; this would have a few obvious "nice" properties
>> > (pun intended).
> Oh I see I misunderstood again :/ Its not about the effective load but weight
> of the initial effective load wrt adjustment.
> 
> Previous schedulers didn't have this aspect at all, so no experience from me
> here. Paul would be the one, since he's ran longest with this stuff.
> 
> That said, I would tend to keep it shorter rather than longer so that it would
> adjust quicker to whatever it really wanted to be.
> 
> Morten says the load is unstable specifically on loaded systems. I would think
> this is because we'd experience scheduling latency, we're runnable more pushing
> things up. But if we're really an idle task at heart we'd not run again for a
> long while, pushing things down again.
> 
> So on that point Paul's suggestion of maybe starting with __sched_slice() might
> make sense because it increases the weight of the initial avg with nr_running.
> 
> Not sure really, we'll have to play and see what works best for a number of
> workloads.


The patch of using sched_slice for review, I am testing the benchmarks

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