Re: Renice X for cpu schedulers

Bill Huey
2007-04-20T05:34:55Z

On Thu, Apr 19, 2007 at 05:20:53PM -0700, Michael K. Edwards wrote:
> Embedded systems are already in 2007, and the mainline Linux scheduler
> frankly sucks on them, because it thinks it's back in the 1960's with
> a fixed supply and captive demand, pissing away "CPU bandwidth" as
> waste heat. Not to say it's an easy problem; even academics with a
> dozen publications in this area don't seem to be able to model energy
> usage to the nearest big O, let alone design a stable economic
> dispatch engine. But it helps to acknowledge what the problem is:
> even in a 1960's raised-floor screaming-air-conditioners
> screw-the-power-bill machine room, you can't actually run a
> half-decent CPU flat out any more without burning it to a crisp.
> stupid. What's your excuse? ;-)

It's now possible to QoS significant parts of the kernel since we now
have a deadline mechanism in place. In the original 2.4 kernel, TimeSys's
irq-thread allowed for the processing of skbuffs in a thread under a CPU
reservation run category which was use to provide QoS I believe. This
basic mechanish can now be generalized to many place in the kernel and
put it under scheduler control.

It's just a matter of who and when somebody is going take on this task.

bill