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    SubjectRe: [PATCH] local_irq_disable removal
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    On Mon, 2005-06-13 at 09:44 +0200, Esben Nielsen wrote:
    > On Mon, 13 Jun 2005, Sven-Thorsten Dietrich wrote:
    >
    > > On Sat, 2005-06-11 at 22:03 +0200, Ingo Molnar wrote:
    > > > * Esben Nielsen <simlo@phys.au.dk> wrote:
    > > >
    > > > > > the jury is still out on the accuracy of those numbers. The test had
    > > > > > RT_DEADLOCK_DETECT (and other -RT debugging features) turned on, which
    > > > > > mostly work with interrupts disabled. The other question is how were
    > > > > > interrupt response times measured.
    > > > > >
    > > > > You would accept a patch where I made this stuff optional?
    > > >
    > > > I'm not sure why. The soft-flag based local_irq_disable() should in fact
    > > > be a tiny bit faster than the cli based approach, on a fair number of
    > > > CPUs. But it should definitely not be slower in any measurable way.
    > > >
    > >
    > > Is there any such SMP concept as a local_preempt_disable() ?
    > >
    > You must think of preempt_disable() ? Except for the interface is a little
    > bit different using flags in local_irq_save(), preempt_disable() works
    > exactly the same way, blocking for everything but interrupts - on the
    > _local_ CPU. (Under PREEMPT_RT it ofcourse also blocks for threaded IRQ
    > handlers.)

    Doesn't preempt_disable() also block rescheduling on other CPUs?

    We only need to prevent rescheduling on THIS CPU.



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