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    SubjectRe: 2.6.14-rt1
    On 11/1/05, Steven Rostedt <> wrote:
    > On Tue, 2005-11-01 at 21:55 -0500, Carlos Antunes wrote:
    > >
    > > Fernando,
    > >
    > > I'm also having some when using SCHED_FIFO and SCHED_RR. When running
    > > several hundred threads, each sleeping on a loop for 20ms, SCHED_OTHER
    > > performs ok with latencies of less than 10ms while with SCHED_FIFO or
    > > SCHED_RR, I see latencies exceeding 1 full second!
    > Are you saying that you have several hundred threads in SCHED_FIFO or
    > SCHED_RR? Or is just Jack as that.

    It's a simple program I put together to test wakeup latency. Each
    thread basically sleeps for 20ms, wakes up and executes a couple of
    instructions and goes back to sleep for another 20ms. Multiply this by
    a thousand. What I found out is that, inthis situation, and using
    realtime-preempt, SCHED_OTHER offers 3 orders of magnitude less
    latency than SCHED_FIFO or SCHED_RR. Which suggests to me there is
    something fishy going on.


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