lkml.org 
[lkml]   [2007]   [Mar]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [rfc][patch] queued spinlocks (i386)
    On Fri, Mar 23, 2007 at 11:04:18AM +0100, Ingo Molnar wrote:
    >> isnt this patented by MS? (which might not worry you SuSE/Novell guys,
    >> but it might be a worry for the rest of the world ;-)

    On Fri, Mar 23, 2007 at 11:32:44AM +0100, Nick Piggin wrote:
    > Hmm, it looks like they have implemented a system where the spinning
    > cpu sleeps on a per-CPU variable rather than the lock itself, and
    > the releasing cpu writes to that variable to wake it. They do this
    > so that spinners don't continually perform exclusive->shared
    > transitions on the lock cacheline. They call these things queued
    > spinlocks. They don't seem to be very patent worthy either, but
    > maybe it is what you're thinking of?

    Those exclusive-to-shared transitions are among the cacheline transfers
    typically accounted to the algorithms in their complexity analyses.


    -- wli
    -
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

    \
     
     \ /
      Last update: 2007-03-23 12:05    [W:0.019 / U:97.920 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site