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SubjectRe: [RFC][PATCH 2/2] ACPI: handle timer ticks proactively
Hi!

> > > This patch takes advantage of the infrastructure introduced in the last
> > > patch, and allows the processor idle algorithm to proactively choose a
> > > c-state based on the time the next timer interrupt is expected to occur.
> > > It preserves the residency metric, so the algorithm should, in theory,
> > > remain effective against bursts of activity from other interrupt
> > > sources.
> > >
> > > This patch is mostly intended to be illustrative. There may be some
> > > "#ifdef CONFIG_ACPI" issues, and I would appreciate any advice on
> > > implementing this more cleanly.
>
> Okay, just to get you some feedback:
>
> It seems to change things a _lot_. Power consumption with usb modules
> loaded went from 14315mW to 13800mW -- that is huge
> deal. Unfortunately something strange is going on: with stock kernel,
> power consumption is mostly constant. With your patch, it varies a
> lot, at 2 second timescale.
>
> Power consumption with usb unloaded (only way to get reasonable power
> on x60) went from stable 10450mW to something rapidly changing, and
> probably even worse than original:

I also noticed that with your patch, bus master activity tends to be constant?!

root@amd:/data/l/tp/tp_smapi-0.22# cat /proc/acpi/processor/CPU0/power
active state: C3
max_cstate: C8
bus master activity: 37244
states:
C1: type[C1] latency[000] usage[00000067]
duration[00000000000000000067]
C2: type[C2] latency[001] usage[00042173]
duration[00000000000454647687]
*C3: type[C3] latency[057] usage[00290242]
duration[00000000003402855375]
root@amd:/data/l/tp/tp_smapi-0.22# cat /proc/acpi/processor/CPU0/power
active state: C3
max_cstate: C8
bus master activity: 37244
states:
C1: type[C1] latency[000] usage[00000067]
duration[00000000000000000067]
C2: type[C2] latency[001] usage[00042274]
duration[00000000000454688808]
*C3: type[C3] latency[057] usage[00305466]
duration[00000000003595077816]
root@amd:/data/l/tp/tp_smapi-0.22#
Pavel
--
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