Re: scheduler (sched_4bsd) questions

From: John Baldwin (jhb_at_FreeBSD.org)
Date: 09/18/04

  • Next message: Stephan Uphoff: "Re: scheduler (sched_4bsd) questions" 
    To: freebsd-arch@FreeBSD.org
Date: Sat, 18 Sep 2004 16:53:35 -0400

    On Saturday 18 September 2004 01:42 pm, Stephan Uphoff wrote:
    > On Fri, 2004-09-17 at 21:20, Julian Elischer wrote:
    > > Stephan Uphoff wrote:
    > > >If this is true kernel threads can be preempted while holding
    > > >for example the root vnode lock (or other important kernel
    > > >resources) while not getting a chance to run until there are no more
    > > >user processes with better priority.
    > >
    > > This is also true, though it is a slightly more complicated thing than
    > > that.
    > > Preempting threads are usually interrupt threads and are thus usually
    > > short lived,.
    >
    > But interrupt threads often wake up other threads ...

    That are lower priority and thus won't be preempted to. Instead, they run
    when the interrupt thread goes back to sleep after it finishes. 

    -- 
John Baldwin <jhb@FreeBSD.org>  <><  http://www.FreeBSD.org/~jhb/
"Power Users Use the Power to Serve"  =  http://www.FreeBSD.org
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  • Next message: Stephan Uphoff: "Re: scheduler (sched_4bsd) questions"