lkml.org 
[lkml]   [2003]   [Aug]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: Ingo Molnar and Con Kolivas 2.6 scheduler patches
On Wednesday 06 August 2003 22:28, Rob Landley wrote:
>> So, how does SCHED_SOFTRR fail? Theoretically there is a minimum timeslice
>> you can hand out, yes? And an upper bound on scheduling latency. So
>> logically, there is some maximum number "N" of SCHED_SOFTRR tasks running
>> at once where you wind up round-robining with minimal timeslices and the
>> system is saturated. At N+1, you fall over. (And in reality, there are
>> interrupts and kernel threads and other things going on that get kind of
>> cramped somewhere below N.)

On Thu, Aug 07, 2003 at 04:42:55PM +0100, Daniel Phillips wrote:
> The upper bound for softrr realtime scheduling isn't based on number
> of tasks, it's a global slice of cpu time: so long as the sum of
> running times of all softrr tasks in the system lies below limit,
> softrr tasks will be scheduled as SCHED_RR, otherwise they will be
> SCHED_NORMAL.

You're thinking of Little's law, which is describes the mean number of
waiters on a queue as the mean service time divided by the number of
servers times the mean inter-arrival time.


-- wli
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 13:47    [W:0.098 / U:1.432 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site