lkml.org 
[lkml]   [1999]   [Feb]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: 2.2.1 scheduler behavior


On Fri, 19 Feb 1999, Rik van Riel wrote:

> On 18 Feb 1999, Claude Gamache wrote:
>
> > We have an application made up of 15 processes that interact
> > through shared memories and sockets. Each process computes for a
> > few milliseconds and then pass its data to the next one (a
> > pipeline computation scheme).
> [SNIP]
>
> > It looks as if the use of the RTC at high frequencies causes the
> > Kernel scheduler to be executed more often.
>
> Andrea, Ingo?

Just to add my 2c, I noticed the same thing with a little module
that repeatedly adds itself to tq_immediate and exports a count to
/proc. It executes either two or four times the interrupt frequency
depending on whether an application selects on rtc or does a blocking
read. Isn't that simply due to scheduling on the interrupt and syscall
returns?

But I noticed something else curious. When I had apm compiled in
along with CONFIG_APM_CPU_IDLE, the task would execute between
30000 to 40000 times per second! Removing apm it went back
the more "normal" 400 to 600.
Just wondering is this the expected behavior?


















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

\
 
 \ /
  Last update: 2005-03-22 13:50    [from the cache]
©2003-2011 Jasper Spaans