lkml.org 
[lkml]   [2004]   [Sep]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: processor affinity
    jmerkey@galt.devicelogics.com wrote:
    > On Thu, Sep 30, 2004 at 12:39:12PM +1000, Nick Piggin wrote:

    >>Of course, I don't really have any idea how to interpret patents...

    ^^^
    keeping that in mind

    >
    > The implementation in NetWare and the Implementation in Linux are
    > similiar but not identical, but they are close enough. CPU bitmasks were
    > used. The best apporach would be for someone to locate prior art in the
    > field and challenge the patent in the event any claims were ever brought
    > or avoid the same methods.

    It seems that the actual patent describes the implementation of the
    scheduler that achieves this. And in it, the method used is a locked
    global queue and unlocked local queues. But anyway.

    > I was able to achieve greater than
    > 100% scaling per processor due to Intel's quirky cache behavior.

    And probably most cache behaviours. If you have a set of tasks with
    a working set larger than the cache of 1 processor but that can be
    divided to fit into the cache of 2, then you're laughing.

    More than 1 CPU can dramatically lower task switch (and mm switch)
    rates in ideal situations, too.

    > If
    > you can get a small subset of code in the cache controllers for
    > processes through hueristics (i.e. guessing) additive processor
    > scaling can be increased dramatically due to taking advantage
    > of the L1 and L2 proceesor caches. Linux is somewhat crude
    > from an SMP perspective even today, although it has an impressive
    > array of hardware support for SMP systems and architectures, but
    > based on the small number of processes than run on average (< 100)
    > this technique would work on Linux.
    >

    Well it has pretty strong CPU affinity, and roughly distributes
    load evenly over CPUs. What more do you want? :)
    -
    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: 2005-03-22 14:06    [W:0.028 / U:0.192 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site