[lkml]   [2005]   [Jun]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
    SubjectRe: [PATCH] local_irq_disable removal
    On Sat, 11 Jun 2005, Ingo Molnar wrote:

    > * Esben Nielsen <> 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.

    Interesting .. So "cli" takes 7 cycles , "sti" takes 7 cycles. The current
    method does "lea" which takes 1 cycle, and "or" which takes 1 cycle. I'm
    not sure if there is any function call overhead .. So the soft replacment
    of cli/sti is 70% faster on a per instruction level .. So it's at least
    not any slower .. Does everyone agree on that?


    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to
    More majordomo info at
    Please read the FAQ at

     \ /
      Last update: 2005-06-11 22:55    [W:0.019 / U:22.968 seconds]
    ©2003-2017 Jasper Spaans. hosted at Digital OceanAdvertise on this site