Re: [PATCH] sched: staircase deadline misc fixes

Con Kolivas
2007-03-28T23:04:39Z

On Thursday 29 March 2007 04:48, Ingo Molnar wrote:
> hm, how about the questions Mike raised (there were a couple of cases of
> friction between 'the design as documented and announced' and 'the code
> as implemented')? As far as i saw they were still largely unanswered -
> but let me know if they are all answered and addressed:

I spent less time emailing and more time coding. I have been working on
addressing whatever people brought up.

> http://marc.info/?l=linux-kernel&m=117465220309006&w=2

Attended to.

> http://marc.info/?l=linux-kernel&m=117489673929124&w=2

Attended to.

> http://marc.info/?l=linux-kernel&m=117489831930240&w=2

Checked fine.

> and the numbers he posted:
>
> http://marc.info/?l=linux-kernel&m=117448900626028&w=2

Attended to.

> his test conclusion was that under CPU load, RSDL (SD) generally does
> not hold up to mainline's interactivity.

There have been improvements since the earlier iterations but it's still a
fairness based design. Mike's "sticking point" test case should be improved
as well.

My call based on my own testing and feedback from users is:

Under niced loads it is 99% in favour of SD.

Under light loads it is 95% in favour of SD.

Under Heavy loads it becomes proportionately in favour of mainline. The
crossover is somewhere around a load of 4.

If the reluctance to renice X goes away I'd say it was 99% across the board
and to much higher loads.

> Ingo

--
-ck