Re: [Lse-tech] Re: CPUSET Proposal

[William Lee Irwin III <wli@holomorphy.com>]

At some point in the past, I wrote:
>> Well, the thing is, CKRM essentially has the cross-resource bits and
>> makes up some group that can be joined and departed from and inherited
>> and so on with all the right knobs ...

On Wed, Sep 24, 2003 at 11:38:04PM -0700, Paul Jackson wrote:
> The hierarchies don't correspond, or do so only accidentally.
> That is, cpusets, as proposed, have a hierarchy such that one
> cpuset is the child of another if one cpuset describes a subset
> of another's CPUs.
> At first blush, I don't see a hierarchy of CKRM Classes, rather
> just a flat space, say Gold, Silver and Bronze.

It's meant to flatten the hierarchy by using numerical measures of
share to precompute the effect of the hierarchy. A directly hierarchical
data structure representation's traversal is too inefficient to be
tolerated in certain performance-critical codepaths, e.g. schedule().

The hierarchy is meant to be there, just implemented without that
traversal in the scheduler (and elsewhere).


-- wli