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    Does linux switch between mulitple cores in CPU?

    Discussion in 'Linux Compatibility and Software' started by wearetheborg, Oct 29, 2009.

  1. wearetheborg

    wearetheborg Notebook Virtuoso

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    I notice in my system monitor that the load on the two cores is such that the load on one is like a mirror image of the load on another. That is, for 2 secs the load on core 1 will be more than the load on core 2, then after that it will switch.
    Is this a deliberate thing on the part of linux, or just an artifact of task scheduling ?
     
    wearetheborg, Oct 29, 2009
    #1
  2. Charr

    Charr Notebook Deity

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    It is deliberate. It would keep each CPU in a mutli-CPU system running cooler, but it has no effect on a mutlicore machine.
     
    Charr, Oct 29, 2009
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  3. wearetheborg

    wearetheborg Notebook Virtuoso

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    Why would it have no effect on a multicore machine ? The cooling area is effectively reduced by spreading heat over the two cores ?
     
    wearetheborg, Oct 29, 2009
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  4. HotBlood

    HotBlood Notebook Consultant

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    Linux will try to balance the cpus.
    Applications can lock themselves to particular CPUs.
     
    HotBlood, Oct 29, 2009
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  5. Peon

    Peon Notebook Virtuoso

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    Wouldn't this kind of thread-bouncing behavior have catastrophic effects on Nehalem's turbo mode?
     
    Peon, Oct 30, 2009
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  6. Charr

    Charr Notebook Deity

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    Turbo doesn't work under Linux, so it can't have any effect. If you need the extra turbo, your going to have to lock the multiplier and voltages in the BIOS.
     
    Charr, Nov 9, 2009
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  7. Peon

    Peon Notebook Virtuoso

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    Surprising... Nehalem is a year old now, but Core i7 is still not fully supported?
     
    Peon, Nov 10, 2009
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  8. Charr

    Charr Notebook Deity

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    It is fully supported, just not by cpufreqd.
     
    Charr, Nov 10, 2009
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