Re: [ckrm-tech] [RFC] [PATCH 0/3] Add group fairness to CFS

[Srivatsa Vaddagiri <vatsa@in.ibm.com>]

On Thu, May 31, 2007 at 02:03:53PM +0530, Srivatsa Vaddagiri wrote:
> Its ->wait_runtime will drop less significantly, which lets it be
> inserted in rb-tree much to the left of those 1000 tasks (and which indirectly
> lets it gain back its fair share during subsequent schedule cycles).
> 
> Hmm ..is that the theory?

My only concern is the time needed to converge to this fair
distribution, especially in face of fluctuating workloads. For ex: a
container who does a fork bomb can have a very adverse impact on other
container's fair share under this scheme compared to other schemes which 
dedicate separate rb-trees for differnet containers (and which also support two 
level hierarchical scheduling inside the core scheduler).

I am inclined to have the core scheduler support atleast two levels of 
hierarchy (to better isolate each container) and resort to the flattening 
trick for higher levels.

-- 
Regards,
vatsa