Re: Stolen and degraded time and schedulers

Jeremy Fitzhardinge
2007-03-14T16:37:21Z

Daniel Walker wrote:
> Then your direction is wrong, sched_clock() should be constant ideally
> (1millisecond should really be 1millisecond).

Rather than repeating myself, I suggest you read my original post
again. But my point is that "I was runnable on a cpu for 1ms of real
time" is a meaningless measurement: you want to measure "I ran for 1
cpu-ms", which is a unit which depends on how work a particular CPU does
in relationship to other CPUs on the system, or even itself at some
previous time.

> Like I said in the last
> email, change the scheduler to make it aware of the variable quantum
> values.

I suppose you could, but that seems more complex. I think you could
encode the same information in the measurement of how much work a cpu
actually got done while a process was scheduled on it.

J