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[Richard Kleeman <kleeman@xxxxxxxxxxxx>]

I tested Brian Roger's 2.6.35-rc5 kernel with the scheduling changes and
saw little difference on a Intel(R) Core(TM)2 Duo CPU (Thinkpad X300).
Here is the powertop output with a firefox browser open:


Wakeups-from-idle per second : 308.9	interval: 15.0s
no ACPI power usage estimate available
Top causes for wakeups:
  30.6% ( 79.3)   [kernel scheduler] Load balancing tick
  19.2% ( 49.9)   [extra timer interrupt]
  16.5% ( 42.9)   [kernel core] hrtimer_start (tick_sched_timer)
   0.1% (  0.3)D  upowerd
   5.9% ( 15.2)   [iwlagn] <interrupt>
   0.3% (  0.8)D  gnome-settings-
   4.6% ( 11.9)   firefox-bin
   4.2% ( 11.0)   nautilus
   3.9% ( 10.0)   syndaemon
   3.1% (  8.1)   [kernel core] usb_hcd_poll_rh_status (rh_timer_func)
   2.2% (  5.7)   [ahci] <interrupt>
   1.6% (  4.3)   [TLB shootdowns] <kernel IPI>
   0.0% (  0.0)D  flush-8:0
   1.2% (  3.1)   Xorg

Compared with the standard Lucid kernel, the Load balancing tick wakeups
are down about 10% while the  hrtimer_start (tick_sched_timer) are up
some.

These results compare with using the Karmic kernel where wakeups were
halved.

Brian: Did you apply the patch noted in the lkml thread I posted above?
The claim there is a substantial wakeups reduction with that applied.

-- 
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
https://bugs.launchpad.net/bugs/524281
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