Re: [PATCH V3 0/22] sched: simplified fork, enable load average intoLB and power awareness scheduling

[Morten Rasmussen]

Hi Alex,

On Sat, Jan 05, 2013 at 08:37:29AM +0000, Alex Shi wrote:
> The patch set base on Linus tree, includes 3 parts,
> 1, bug fix and fork/wake balancing clean up. patch 1~6,
> the first patch remove one domain level. patch 2~6 simplified fork/wake
> balancing, it can increase 10+% hackbench performance on our 4 sockets
> SNB EP machine.
> 
> V3 change:
> a, added the first patch to remove one domain level on x86 platform.
> b, some small changes according to Namhyung Kim's comments, thanks!
> 
> 2, bug fix for load average and implement it into LB, patch 7~12,
> That using load average in load balancing, with a initial runnable load
> value bug fix.
> 
> V3 change:
> a, use rq->cfs.runnable_load_avg as cpu load not
> rq->avg.load_avg_contrib, since the latter need much time to accumulate
> for new forked task,
> b, a build issue fixed with Namhyung Kim's reminder.
> 
> 3, power awareness scheduling, patch 13~22,
> The subset implement my previous power aware scheduling proposal:
> https://lkml.org/lkml/2012/8/13/139
> It defines 2 new power aware policy balance and powersaving, and then
> try to spread or pack tasks on each of sched group level according the
> different scheduler policy. That can save much power when task number in
> system is no more then LCPU number.

Interesting stuff. I have read through your patches, but it is still not
clear to me what metrics you use to determine whether a sched group is
fully utilized or if it can be used for packing more tasks. Is it based on
nr_running or PJT's tracked load or both? How is the threshold defined?

Best regards,
Morten

> 
> V3 change:
> a, engaged nr_running in max potential utils consideration in periodic
> power balancing.
> b, try exec/wake small tasks on running cpu not idle cpu.
> 
> Thanks comments on previous version. and Any more comments are appreciated!
> 
> -- Thanks Alex
> 
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