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

From: Srivatsa Vaddagiri
Date: Thu May 31 2007 - 04:49:06 EST


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
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