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cpu frequency

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Bob Tennent

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Nov 30, 2009, 7:47:48 PM11/30/09
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One of my systems has the following cpuinfo:

processor : 0
vendor_id : GenuineIntel
cpu family : 6
model : 15
model name : Intel(R) Core(TM)2 Duo CPU E6550 @ 2.33GHz
stepping : 11
cpu MHz : 1866.690
cache size : 4096 KB
:

and similarly for processor 1.

My question is: why would the cpu frequency be 1866.69 MHz instead of
2.33GHz? Is the BIOS or a jumper not set properly? On my other systems,
the @ frequency and the cpu frequencies agree.

Bob T.

Grant

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Nov 30, 2009, 8:29:14 PM11/30/09
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Because wit hthe Core2Duo the CPU idles at 6/9 max freq. Try doing
cpuinfo while your system is busy, for example during a kernel compile,
and you see the CPU at max freq.

Grant.
--
http://bugsplatter.id.au

AZ Nomad

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Nov 30, 2009, 8:39:15 PM11/30/09
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On Tue, 1 Dec 2009 00:47:48 +0000 (UTC), Bob Tennent <Bo...@cs.queensu.ca> wrote:

sounds like you have clock throttling enabled. The cpu is slowed down
when demand is less to reduce power.

Lusotec

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Dec 1, 2009, 4:55:20 AM12/1/09
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Probably the CPU is under a *low* load and the kernel has reduced the CPU's
frequency to reduce heat generation, temperature and power consumption.

Information about CPU frequencies can be seen in the files in the directory:
/sys/devices/system/cpu/cpu0/cpufreq/

All the files have a self explanatory name. In particular the file
scaling_available_frequencies contains the available frequencies for the
CPU.

Regards.

Bob Tennent

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Dec 1, 2009, 8:14:13 AM12/1/09
to

Thanks to all for the responses. But I'm still mystified. The CPU was
fully "loaded" because of a problem with qemu-kvm, the cpuspeed daemon
wasn't running, and 1866 isn't one of the "available" frequencies:

% cat /sys/devices/system/cpu/cpu*/cpufreq/scaling_available_frequencies
2331000 1998000
2331000 1998000

Anyway, after starting cpuspeed and stopping qemu-kvm, I'm now getting

model name : Intel(R) Core(TM)2 Duo CPU E6550 @ 2.33GHz

cpu MHz : 1998.000

Bob T.

AZ Nomad

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Dec 1, 2009, 9:54:16 AM12/1/09
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You don't need cpuspeed running if you have a cpu frequency governor
compiled into the kernel.

do a grep CPU_FREQ /lib/modules/`uname -r`/build/.config


Bob Tennent

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Dec 1, 2009, 3:54:16 PM12/1/09
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On Tue, 01 Dec 2009 09:55:20 +0000, Lusotec wrote:

> Information about CPU frequencies can be seen in the files in the directory:
> /sys/devices/system/cpu/cpu0/cpufreq/

Why would this directory not exist? Presumably that would explain why I'm getting

% sudo modprobe acpi_cpufreq
FATAL: Error inserting acpi_cpufreq (/lib/modules/../cpu/cpufreq/acpi-cpufreq.ko):
No such device

Bob T.

ShadowTek

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Dec 1, 2009, 5:03:33 PM12/1/09
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On 2009-12-01, Bob Tennent <Bo...@cs.queensu.ca> wrote:
>
> Thanks to all for the responses. But I'm still mystified. The CPU was
> fully "loaded" because of a problem with qemu-kvm, the cpuspeed daemon
> wasn't running, and 1866 isn't one of the "available" frequencies:

I recently built a new system, and my core2duo wasn't running at the
right frequency at first. It seems that the BIOS came shipped with the
"failsafe" defaults active, and I had to load the "optimized" profile
before everything registered properly.

Frank Steinmetzger

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Dec 1, 2009, 5:04:28 PM12/1/09
to
Bob Tennent schrob:

> Thanks to all for the responses. But I'm still mystified. The CPU was
> fully "loaded" because of a problem with qemu-kvm, the cpuspeed daemon
> wasn't running, and 1866 isn't one of the "available" frequencies:
>
> % cat /sys/devices/system/cpu/cpu*/cpufreq/scaling_available_frequencies
> 2331000 1998000
> 2331000 1998000
>
> Anyway, after starting cpuspeed and stopping qemu-kvm, I'm now getting
>
> model name : Intel(R) Core(TM)2 Duo CPU E6550 @ 2.33GHz
> cpu MHz : 1998.000

Until recently, my laptop had a thermal problem. The CPU could go up to
2GHz, but when I put it under load in Windows, it would reach 90°C and
more. On the other hand, the linux governor automatically lowered the
frequency when the CPU reached about 85°, so instead of 2GHz, it was mostly
running at 1,3 when I was compiling/rendering stuff.

Last week I cleaned the fan outlet and renewed the system’s thermal paste,
and now it’s all fine again. So perhaps you could look at the temperature
as well.
--
Gruß | Greetings | Qapla'
Auf Almen darf man sorglos lieben, denn im Herbst wird abgetrieben.

Hactar

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Dec 1, 2009, 5:20:23 PM12/1/09
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In article <slrnhhb0j...@linus.cs.queensu.ca>,

Look in the kernel source, in:
Power management options --->
CPU Frequency scaling --->

Make sure this is checked:
[*] CPU Frequency scaling

It depends on !X86_VOYAGER (no, I don't know what X86_VOYAGER is).

Make sure the appropriate ones of these are (set to be) compiled:
'performance' governor
'powersave' governor
'userspace' governor for userspace frequency scaling
'ondemand' cpufreq policy governor
'conservative' cpufreq governor

plus whichever one of these is relevant:
ACPI Processor P-States driver
AMD Opteron/Athlon64 PowerNow!
Intel Enhanced SpeedStep (deprecated)
Intel Pentium 4 clock modulation

--
-eben QebWe...@vTerYizUonI.nOetP royalty.mine.nu:81
PISCES: Try to avoid any Virgos or Leos with the Ebola
virus. You are the Lord of the Dance, no matter what those
idiots at work say. -- Weird Al, _Your Horoscope for Today_

Bob Tennent

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Dec 1, 2009, 11:06:43 PM12/1/09
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% grep CPU_FREQ /lib/modules/`uname -r`/build/.config
CONFIG_CPU_FREQ=y
CONFIG_CPU_FREQ_TABLE=y
CONFIG_CPU_FREQ_DEBUG=y
CONFIG_CPU_FREQ_STAT=m
CONFIG_CPU_FREQ_STAT_DETAILS=y
# CONFIG_CPU_FREQ_DEFAULT_GOV_PERFORMANCE is not set
# CONFIG_CPU_FREQ_DEFAULT_GOV_POWERSAVE is not set
CONFIG_CPU_FREQ_DEFAULT_GOV_USERSPACE=y
# CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND is not set
# CONFIG_CPU_FREQ_DEFAULT_GOV_CONSERVATIVE is not set
CONFIG_CPU_FREQ_GOV_PERFORMANCE=y
CONFIG_CPU_FREQ_GOV_POWERSAVE=m
CONFIG_CPU_FREQ_GOV_USERSPACE=y
CONFIG_CPU_FREQ_GOV_ONDEMAND=m
CONFIG_CPU_FREQ_GOV_CONSERVATIVE=m

% grep ACPI_CPUFREQ /lib/modules/`uname -r`/build/.config
CONFIG_X86_ACPI_CPUFREQ=m

I can modprobe cpufreq_ondemand and cpufreq_stats, but not acpi-cpufreq.

Bob T.

Message has been deleted

Bob Tennent

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Dec 2, 2009, 7:12:25 AM12/2/09
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On Wed, 2 Dec 2009 00:12:46 -0500, Hactar wrote:
> In article <slrnhhbpu...@linus.cs.queensu.ca>,
> When I do that I get a similar output.
>
> Huh. I just tried to load acpi-cpufreq.ko and got:
> ,--
>| FATAL: Error inserting acpi_cpufreq
>| (/lib/modules/2.6.26.5/kernel/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.ko):
>| No such device
> '--
>
> It accepts processor.ko .
>
> I swear it used to work. Good thing I'm not on a laptop. Is this the
> error you're getting?

Yes, except that my kernel is 2.6.30.9-99.fc11.i686.PAE

Darren Salt

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Dec 2, 2009, 1:53:06 PM12/2/09
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I demand that Bob Tennent may or may not have written...

> On Wed, 2 Dec 2009 00:12:46 -0500, Hactar wrote:
>> In article <slrnhhbpu...@linus.cs.queensu.ca>,
>> Bob Tennent <rdte...@gmail.com> wrote:

[snip]


>>> % grep CPU_FREQ /lib/modules/`uname -r`/build/.config
>>> CONFIG_CPU_FREQ=y
>>> CONFIG_CPU_FREQ_TABLE=y
>>> CONFIG_CPU_FREQ_DEBUG=y
>>> CONFIG_CPU_FREQ_STAT=m
>>> CONFIG_CPU_FREQ_STAT_DETAILS=y
>>> # CONFIG_CPU_FREQ_DEFAULT_GOV_PERFORMANCE is not set
>>> # CONFIG_CPU_FREQ_DEFAULT_GOV_POWERSAVE is not set
>>> CONFIG_CPU_FREQ_DEFAULT_GOV_USERSPACE=y
>>> # CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND is not set
>>> # CONFIG_CPU_FREQ_DEFAULT_GOV_CONSERVATIVE is not set
>>> CONFIG_CPU_FREQ_GOV_PERFORMANCE=y
>>> CONFIG_CPU_FREQ_GOV_POWERSAVE=m
>>> CONFIG_CPU_FREQ_GOV_USERSPACE=y
>>> CONFIG_CPU_FREQ_GOV_ONDEMAND=m
>>> CONFIG_CPU_FREQ_GOV_CONSERVATIVE=m

>>> % grep ACPI_CPUFREQ /lib/modules/`uname -r`/build/.config
>>> CONFIG_X86_ACPI_CPUFREQ=m

$ zgrep 'CPU_\?FREQ' /proc/config.gz |grep -v ^#
CONFIG_CPU_FREQ=y
CONFIG_CPU_FREQ_TABLE=y
CONFIG_CPU_FREQ_STAT=y
CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND=y
CONFIG_CPU_FREQ_GOV_PERFORMANCE=y
CONFIG_CPU_FREQ_GOV_ONDEMAND=y
CONFIG_X86_ACPI_CPUFREQ=y
$

(CPU is an Athlon 64.)

[snip]
> my kernel is 2.6.30.9-99.fc11.i686.PAE

Noting from earlier in the thread that you're using a Core2, you could be
running a 64-bit kernel on it without throwing away your 32-bit userland.

--
| Darren Salt | linux at youmustbejoking | nr. Ashington, | Doon
| using Debian GNU/Linux | or ds ,demon,co,uk | Northumberland | Army
| + http://www.xine-project.org/

To catch intelligent fish, you use a neural net.

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