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    SubjectRe: report a bug about sched_rt
    From
    2009/7/24 Peter Zijlstra <peterz@infradead.org>:
    > On Fri, 2009-07-24 at 21:44 +0800, sen wang wrote:
    >> 2009/7/24 Peter Zijlstra <peterz@infradead.org>:
    >> > On Fri, 2009-07-24 at 21:26 +0800, sen wang wrote:
    >> >> don't tell me what theory. don't be so doctrinairism! OK?
    >> >> If cpu is free and there is a running state task,how can you scdedule
    >> >> idle task up?
    >> >> I tell you again:we are not talking about a bandwidth of 100% for RT!
    >> >> Bug lies in the bandwidth of (100- X)%.(X<100)
    >> >> even in the time of 100-X,if there is a rt task, you should not idle()
    >> >> the system.
    >> >
    >> > *sigh*
    >> >
    >> > Yes we should. I appreciate that you might assume otherwise, but you're
    >> > wrong. Suppose you have two competing bandwidth groups, which one will
    >> > run over, to what purpose?
    >> >
    >> > Also, your next top post will go to /dev/null.
    >> >
    >>
    >>
    >> OK !  maybe you has not understand what I said.
    >> It not two competing bandwidth groups. there is a  active group and
    >> another is empty?
    >> How you do?
    >
    > No, but the 1 group is the trivial case of many groups. Changing the
    > semantics for the trivial case is inconsistent at best, and confusing at
    > worst.
    >
    >> Why not try it by your hand: empty the fair task, run a rt task,enable
    >> the  bandwidth and
    >> see what will happen!
    >
    > Oh, I know, I wrote the code.
    >
    >> In many embedded system,idle task will lead to shutdown something, but
    >> the rt task will
    >> assume: when it run, idle will not happen!
    >
    > How is it my problem when you design your system wrong?
    >
    > If you want your 1 RT group to not get throttled, disable the throttle,
    > or adjust it to fit the parameters of your workload. If you don't want
    > idle to have latency impact on your RT tasks, fix your idle behaviour.
    >
    >
    >

    OK
    just one question:
    if cpu is free and there is running state task, how you do?
    schedule the task up? or schedule idle task up?
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