[lkml]   [2007]   [Feb]   [6]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
    SubjectRe: 2.6.20-rc6-mm3

    * Daniel Walker <> wrote:

    > > it's quite easy to explain: because of the new dynticks feature.
    > > Both 'timer' and 'LOC' counts go way down.
    > I don't have that enabled tho .. This is with HRT/dynamic tick both
    > off..

    your kernel utilizes the kernelin a more optimal way: the new
    clockevents code now utilizes the local APIC timer irq (represented by
    the LOC field) for periodic interrupts. The local APIC timer irq has a
    cost of ~2 usecs per IRQ, while the PIT irq is ~10 usecs per irq. With
    HZ=1000 this means savings of ~8000 usecs per second - i.e. 8 msecs per
    second, which is 0.8% more raw CPU power available - which isnt that

    we could make this clearer by renaming 'LOC' (which stands for 'LOCal
    timer interupts' and was added [and misnamed] by yours truly many moons
    ago) to 'apic-timer' and 'timer' to 'PIT-timer' but /that/ would be more
    of a userspace visible change than the change in the counter rates.

    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: 2007-02-06 22:13    [W:0.024 / U:60.208 seconds]
    ©2003-2017 Jasper Spaans. hosted at Digital OceanAdvertise on this site