Re: [PATCH] V-3.0 Single Priority Array O(1) CPU Scheduler Evaluation

William Lee Irwin III
2004-08-03T02:03:56Z

>> Hmm. Given do_promotions() I'd expect fenceposts, not iteration over
>> the priority levels of the runqueue.

On Tue, Aug 03, 2004 at 10:33:36AM +1000, Peter Williams wrote:
> I don't understand what you mean. Do you mean something like the more
> complex promotion mechanism in the (earlier) EBS scheduler where tasks
> only get promoted if they've been on a queue without being serviced
> within a given time?

An array of size N can be rotated in O(1) time if an integer is kept
along with it to represent an offset that has to be added to externally-
visible indices mod N to recover the true index.

-- wli