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    Subject[Question] Hooks for scheduler tracing (CFS)
    Hello,

    I am looking for some tool/kernel machanism that enables me to track
    every schedule change on the CFS scheduler of the RT-kernel for some
    period of time.
    Thus a tool that gives me an overview after some time which task got
    "scheduled in/out" at "which timestamp" and at "which CPU". ( I need
    the raw data)

    In a far past (on Montavista kernels) I used LTT for this to log for
    some time with only the SCHED_CHANGE filter and text output. But, I
    cannot find any LTT(ng) support for any RT-kernel, and support for the
    new CFS (like in 2.6.22.1-rt4) is even harder.

    So I was wondering if anybody knows some tool/kernel mechanism which
    can do this?
    If not, I will build a kernel extension for it myself (new extension
    to 'latency_trace' ?)
    In that case can anybody with in depth CFS scheduler knowledge please
    point me which hooks are safe to use for this?

    I need it to get a detailed insight in my RT-system with its RT and
    non-RT applications.
    Thus to know when a certain task gets scheduled (and to calculate its
    per thread min/max/avg latencies), which task preempts another task,
    and to get a complete overview of what the RT system (and scheduler)
    is doing during time etc.


    Kind Regards,

    Remy Böhmer
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