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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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