Questions about ULE and Priority Propagation

From: Andrea Vacondio (andrea.vacondio_at_fastwebnet.it)
Date: 01/29/04

  • Next message: Scott DF: "Re: Page fault while in kernel mode" 
    To: freebsd-current@freebsd.org
Date: Thu, 29 Jan 2004 16:17:19 +0100

    Hi all, i'm writing a document on schedulers in modern OS.. i've some
    questions about the FreeBSD ULE scheduler..
    First of all i couldnt find a good explanation for "priority
    propagation", how does it work??
    Second and most important,i'm reading Jeff Roberson documents about ULE,
    he says there are 2 queues, current and next.. the scheduler picks up
    from current queue and when its empty next and current r switched. This
    guarantees fairness, but later it's written that any intrrupt,
    real-time and iteractive thread is inserted into current queue..given
    this, i'm wondering if it could happen that a lot of real-time or
    interective threads prevent queues swithing..perhaps i'm missing
    something..
    thank you in advance
    Andrea
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  • Next message: Scott DF: "Re: Page fault while in kernel mode"

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