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    SubjectRe: [PATCH 2/2] Convert PowerPC macro spin_event_timeout() to architecture independent macro
    On 07/31/2013 07:04 PM, Stephen Boyd wrote:
    > If it yields why are we using udelay? Why not usleep_range()? It would
    > be useful to have a variant that worked in interrupt context and it
    > looked like that was almost possible.

    I've never heard of usleep_range() before, so I don't know if it
    applies. Apparently, udelay() includes its own call to cpu_relax(). Is
    it possible that cpu_relax() is a "lightweight" yield, compared to sleeping?

    FYI, you might want to look at the code reviews for spin_event_timeout()
    on the linuxppc-dev mailing list, back in March 2009.

    --
    --
    Timur Tabi


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