sched: Remove irq time from available CPU power

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The idea was suggested by Peter Zijlstra here:

  http://marc.info/?l=linux-kernel&m=127476934517534&w=2

irq time is technically not available to the tasks running on the CPU.
This patch removes irq time from CPU power piggybacking on
sched_rt_avg_update().

Tested this by keeping CPU X busy with a network intensive task having 75%
oa a single CPU irq processing (hard+soft) on a 4-way system. And start seven
cycle soakers on the system. Without this change, there will be two tasks on
each CPU. With this change, there is a single task on irq busy CPU X and
remaining 7 tasks are spread around among other 3 CPUs.

Signed-off-by: Venkatesh Pallipadi <venki@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1286237003-12406-8-git-send-email-venki@google.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

...

This commit is contained in:

Venkatesh Pallipadi 2010-10-04 17:03:22 -07:00 • committed by Ingo Molnar

parent 305e6835e0

commit aa48380851

3 changed files with 30 additions and 1 deletions

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18

kernel/sched.c

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8

kernel/sched_fair.c

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5

kernel/sched_features.h

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