Dumb question about Voluntary Kernel Preemption Patch

From: Timothy Miller (miller_at_techsource.com)
Date: 07/15/04

  • Next message: Martin Mares: "Re: PCI configuration changes getting lost." 
    Date:	Thu, 15 Jul 2004 16:11:48 -0400
To: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>

    I sent this before, but I didn't get a response. Either people missed
    it or it wasn't worth responding to. I'll give it one more try before I
    shut up about it...

    I have a question about voluntary kernel preemption in general.
    (Shouldn't we call this "cooperative multitasking"?)

    There are two disadvantages to voluntary preemption. One is that the
    kernel thread my not sleep enough (high latency), and the other is that
    the kernel thread may sleep too much (wasted CPU for context switch
    overhead). The advantage of using the timer interrupt instead is that
    the preemption happens only as often as it needs to.

    My question is this: Do your reschedule points (might_sleep or whatever
    you end up using) ALWAYS reschedule, or do they only reschedule after a
    certain period of time (timer interrupt increments counter, and
    reschedule point does nothing if it's too early)?

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  • Next message: Martin Mares: "Re: PCI configuration changes getting lost."

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