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SubjectRe: acpi_idle: Very idle Core i7 machine never enters C3
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Hi,
can you show me the file /proc/acpi/processor/CPU*/power.
and are you sure your cpu usage is 0 or nearly zero.

this is the info of my laptop(using core 2 processors):
powertop's output:
Cn Avg residency P-states (frequencies)
C0 (cpu running) (10.6%) 2.00 Ghz 1.9%
C0 0.0ms ( 0.0%) 1.67 Ghz 0.1%
C1 mwait 0.0ms ( 0.0%) 1333 Mhz 0.0%
C2 mwait 0.0ms ( 0.0%) 1000 Mhz 98.0%
C3 mwait 1.1ms (89.4%)


and power things:
huang@huang-laptop:~$ cat /proc/acpi/processor/CPU0/power
active state: C0
max_cstate: C8
maximum allowed latency: 2000000000 usec
states:
C1: type[C1] promotion[--] demotion[--]
latency[001] usage[00002364] duration[00000000000000000000]
C2: type[C2] promotion[--] demotion[--]
latency[001] usage[00070662] duration[00000000000006013816]
C3: type[C3] promotion[--] demotion[--]
latency[017] usage[04774185] duration[00000000010838418152]

you can see C3 with powertop,so i think your BIOS has enabled Deep
C-state.

-huang

2010-01-26 (火) の 02:47 -0600 に Jeff Garrett さんは書きました:
> Hi,
>
> I was trying to chase down a theory that my desktop machine (a core i7)
> is running warm (the fan sounds like it's at full speed all the time,
> and I think it's not always acted this way -- hence the theory).
>
> powertop is never showing it spending any time in C3...
>
> I compiled a kernel without USB/sound/radeon, and ran without X. I was
> able to get the wakeups/sec down below 20, but no time is spent in C3.
>
> sysfs looks to agree with powertop here (time = 0 on C3):
> /sys/devices/system/cpu/cpu0/cpuidle/state0/desc: CPUIDLE CORE POLL IDLE
> /sys/devices/system/cpu/cpu0/cpuidle/state0/latency: 0
> /sys/devices/system/cpu/cpu0/cpuidle/state0/name: C0
> /sys/devices/system/cpu/cpu0/cpuidle/state0/power: 4294967295
> /sys/devices/system/cpu/cpu0/cpuidle/state0/time: 457
> /sys/devices/system/cpu/cpu0/cpuidle/state0/usage: 59
> /sys/devices/system/cpu/cpu0/cpuidle/state1/desc: ACPI FFH INTEL MWAIT 0x0
> /sys/devices/system/cpu/cpu0/cpuidle/state1/latency: 1
> /sys/devices/system/cpu/cpu0/cpuidle/state1/name: C1
> /sys/devices/system/cpu/cpu0/cpuidle/state1/power: 1000
> /sys/devices/system/cpu/cpu0/cpuidle/state1/time: 308177
> /sys/devices/system/cpu/cpu0/cpuidle/state1/usage: 3975
> /sys/devices/system/cpu/cpu0/cpuidle/state2/desc: ACPI FFH INTEL MWAIT 0x10
> /sys/devices/system/cpu/cpu0/cpuidle/state2/latency: 17
> /sys/devices/system/cpu/cpu0/cpuidle/state2/name: C2
> /sys/devices/system/cpu/cpu0/cpuidle/state2/power: 500
> /sys/devices/system/cpu/cpu0/cpuidle/state2/time: 873440787
> /sys/devices/system/cpu/cpu0/cpuidle/state2/usage: 239038
> /sys/devices/system/cpu/cpu0/cpuidle/state3/desc: ACPI FFH INTEL MWAIT 0x20
> /sys/devices/system/cpu/cpu0/cpuidle/state3/latency: 17
> /sys/devices/system/cpu/cpu0/cpuidle/state3/name: C3
> /sys/devices/system/cpu/cpu0/cpuidle/state3/power: 350
> /sys/devices/system/cpu/cpu0/cpuidle/state3/time: 0
> /sys/devices/system/cpu/cpu0/cpuidle/state3/usage: 0
>
> This may be a complete red herring, but I added some printk logic to
> acpi_idle_bm_check(), and it is getting called often, but bm_status is
> always 1. [I infer from this that the idle logic is trying to go into
> C3, but this check is stopping it... Unless I misread something.]
>
> Is this expected behavior or is this a legitimate problem?
>
> How might I investigate this further?
>
> Attaching dmesg, /proc/cpuinfo, powertop -d output.
>
> Thanks,
> Jeff Garrett


--
peng huang <huangpeng.linux@gmail.com>

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