lkml.org 
[lkml]   [2009]   [Jan]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [BUG] How to get real-time priority using idle priority

* Mike Galbraith <efault@gmx.de> wrote:

> On Tue, 2009-01-13 at 03:58 +0100, Mike Galbraith wrote:
> > On Mon, 2009-01-12 at 17:05 -0800, Brian Rogers wrote:
>
> > > I'll try Mike's "more complete" patch on top of 2.6.29-rc1 and see what
> > > that does.
> >
> > Don't bother. I just tried a SCHED_IDLE make -j8 and had character
> > repeats while typing. Must be another spot.
>
> Hrmph, what an annoying problem. The below works pretty well, but
> _still_ has latency problems in some circumstances.
>
> The more I look at this, the more I think these guys _really_ want to be
> a separate class. The problem is the incredible rate of min_vruntime
> advancement creating absurdly huge spreads.
>
> Hm, maybe I could advance min_vruntime at nice 0 when these guys are
> running, only advance their vruntime at warp 512, but that seems awfully
> hackish. If they were a separate class, they could use the full nice
> spectrum instead of being merely mega-nice.

A separate class has its own set of problems: starvation, etc.

What about increasing the weight of SCHED_IDLE tasks from 1 to 2 or 3?
That still makes them mega-nice (which is more than enough), but should
make the math a lot less borderline.

Ingo


\
 
 \ /
  Last update: 2009-01-14 06:33    [W:0.079 / U:0.388 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site