[lkml]   [1999]   [Feb]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
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

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
Please read the FAQ at

 \ /
  Last update: 2005-03-22 13:50    [from the cache]
©2003-2014 Jasper Spaans. hosted at Digital Ocean