Nick Piggin wrote:
> Chen, Kenneth W wrote:
> 
>> Revert commit d7102e95b7b9c00277562c29aad421d2d521c5f6,
>> which causes more than 10% performance regression with aim7.
>>
> 
> Just to be sure, what kernel did you test with? In particular,
> did it have the smpnice patch reverted (as -rc3 does).
> 

Analysis of the smpnice code indicates that it could cause anomalous cpu 
selection decisions in try_to_wake_up() if there is a skew in the 
distribution of nice among the tasks on the cpus under consideration. 
Attached for review is a proposed patch to address problem. In 
particular, I request comments on the following issues:

1. Is this potential problem worth worrying about?
2. Do you agree with my decision to replace SCHED_LOAD_SCALE with the 
average load per task for this_cpu in the if statement in 
try_to_wake_up() or should I be using the average load per task for the 
tasks current cpu in one or both places?

Signed-off-by: Peter Williams <pwil3058@bigpond.com.au>

Peter
-- 
Peter Williams                                   pwil3058@bigpond.net.au

"Learning, n. The kind of ignorance distinguishing the studious."
  -- Ambrose Bierce