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    From
    SubjectRe: 2.6.16-rc6-mm2
    Date
    On Tuesday 13 June 2006 07:08, Keith Owens wrote:
    > Andi Kleen (on Tue, 13 Jun 2006 06:56:45 +0200) wrote:
    > >
    > >> I have previously suggested a lightweight solution that pins a process
    > >> to a cpu
    > >
    > >That is preempt_disable()/preempt_enable() effectively
    > >It's also light weight as much as these things can be.
    >
    > The difference being that preempt_disable() does not allow the code to
    > sleep. There are some places where we want to use cpu local data
    > and
    > the code can tolerate preemption and even sleeping, as long as the
    > process schedules back on the same cpu.

    Seems like a pretty obscure case to optimize for.

    Anyways if you want to do that you can always do

    disable_preempt();
    set thread affinity mask to current cpu
    enable_preempt();
    do weird stuff and sleep ... ;
    restore affinity mask

    Can any of these people proposing "solutions" in this thread
    demonstrate this stuff is actually performance critical?

    -Andi
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