Re: [patch] CFS scheduler, -v14

[Li Yu <raise.sail@gmail.com>]

Ingo Molnar wrote:
> i'm pleased to announce release -v14 of the CFS scheduler patchset.
>
> The CFS patch against v2.6.22-rc2, v2.6.21.1 or v2.6.20.10 can be 
> downloaded from the usual place:
>    
>       http://people.redhat.com/mingo/cfs-scheduler/
>   

In comment before distribute_fair_add(), we have such text:

/*
  * A task gets added back to the runnable tasks and gets
  * a small credit for the CPU time it missed out on while
  * it slept, so fix up all other runnable task's wait_runtime
  * so that the sum stays constant (around 0).
  *
[snip]
  */

But as I observe by cat /proc/sched_debug (2.6.21.1, UP, RHEL4), I found 
the all waiting fields often are more than zero, or less than zero.

IMHO, the sum of task_struct->wait_runtime just is the denominator of 
all runnable time in some ways, is it right? if so, increasing the sum 
of wait_runtime just make scheduling decision more precise. so what's 
meaning for keeping the wait_runtime is zero-sum?

Good luck

- Li Yu