Re: RSDL v0.31

From: Ingo Molnar
Date: Sat Mar 17 2007 - 08:45:55 EST



* jos poortvliet <jos@xxxxxxxxxxxx> wrote:

> Op Saturday 17 March 2007, schreef Ingo Molnar:
> > so it is not at all clear to me that RSDL is indeed an improvement,
> > if it does not have comparable auto-nice properties.
>
> Wasn't the point of RSDL to get rid of the auto-nice, because it
> caused starvation, unpredictable behaviour and other problems?

it doesnt really get rid of it, it replaces it with another mechanism
that is fundamentally unfair too.

RSDL has _another_, albeit more hidden "auto-nice" behavior: this time
expressed not via the plain manipulation of priorities based on the
sleep average, but expressed via the quota-depletion flux of tasks over
time, fed into a complex dance of rotating priorities - which
quota-depletion flux is in essence a sleep average too, just more
derived and more hardcoded.

or looking at it from another angle, code size:

text data bss dec hex filename
15750 24 6008 21782 5516 sched.o.vanilla
15960 360 6336 22656 5880 sched.o.rsdl

there's no reduction in complexity, it just moved elsewhere.

Ingo
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