Messages in this thread |  | | | Date | Fri, 19 Feb 1999 01:13:19 -0600 (CST) | | From | "Robert B. Hamilton" <> | | Subject | Re: 2.2.1 scheduler behavior |
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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?
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