The cpu_load decays on time according past cpu load of rq. New sched_avg decays
on tasks' load of time. Now we has 2 kind decay for cpu_load. That is a kind of
redundancy. And increase the system load in sched_tick etc.
This patch trying to remove the cpu_load decay. And fixed a nohz_full bug by
the way.
There are 5 load_idx used for cpu_load in sched_domain. busy_idx and idle_idx
are not zero usually, but newidle_idx, wake_idx and forkexec_idx are all zero
on every arch. A shortcut to remove cpu_Load decay in the first patch. just one
line patch for this change. :)
I have tested the patchset on my pandaES board, 2 cores ARM Cortex A9.
hackbench thread/pipe performance increased nearly 10% with this patchset! That
do surprise me!
latest kernel 527d1511310a89 + this patchset
hackbench -T -g 10 -f 40
23.25" 21.7"
23.16" 19.99"
24.24" 21.53"
hackbench -p -g 10 -f 40
26.52" 22.48"
23.89" 24.00"
25.65" 23.06"
hackbench -P -g 10 -f 40
20.14" 19.37"
19.96" 19.76"
21.76" 21.54"
The git tree for this patchset at:
g...@github.com:alexshi/power-scheduling.git no-load-idx
Since Fengguang had included this tree into his kernel testing system. and I
haven't get a regression report until now. I suppose it is fine for x86 system.
But anyway, since the scheduler change will effect all archs. and hackbench is
only benchmark I found now for this patchset. I'd like to see more testing and
talking on this patchset.
Regards
Alex
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