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

From: Peter Williams
Date: Wed May 30 2007 - 00:08:11 EST


William Lee Irwin III wrote:
On Wed, May 30, 2007 at 10:09:28AM +1000, Peter Williams wrote:
So what you're saying is that you think dynamic priority (or its equivalent) should be used for load balancing instead of static priority?

It doesn't do much in other schemes, but when fairness is directly
measured by the dynamic priority, it is a priori more meaningful.
This is not to say the net effect of using it is so different.

I suspect that while it's probably theoretically better it wouldn't make much difference on a real system (probably not enough to justify any extra complexity if there were any). The exception might be on systems where there were lots of CPU intensive tasks that used relatively large chunks of CPU each time they were runnable which would give the load balancer a more stable load to try and balance. It might be worth the extra effort to get it exactly right on those systems. On most normal systems this isn't the case and the load balancer is always playing catch up to a constantly changing scenario.

Peter
--
Peter Williams pwil3058@xxxxxxxxxxxxxx

"Learning, n. The kind of ignorance distinguishing the studious."
-- Ambrose Bierce
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