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#1 2014-07-27 04:49:13

RankoKohime
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Registered: 2014-01-08
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Haswell Refresh processor running at full speed

I'm running a 4790k, and in all the speed monitoring programs I have, it's showing it running between 4 and 4.4GHz constantly.  Comparably, on Ubuntu 14.04, or Mint 17, the processor scales down to 800MHz at idle, with accompanying lower temperatures (measured through lm_sensors) and power consumption at the wall (measured with a Kill-A-Watt).

Setting a manual value into /sys/devices/system/cpu/intel_pstate/max_perf_pct causes the processor to scale to whatever I set it to, and causes power consumption to scale accordingly.

Did I neglect to install some package, (I have intel_pstate), is proper support for this new processor in the pipeline still, or is there some manual configuration that needs to be done?

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#2 2014-07-27 06:55:21

graysky
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Re: Haswell Refresh processor running at full speed

Which programs?  Build i7z-git from the AUR for your CPU.


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#3 2014-07-27 07:17:41

RankoKohime
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Re: Haswell Refresh processor running at full speed

Every program I've tested, i7z-git included.  It reports 4300-4400MHz when max_perf_pct is set to 100.

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#4 2014-07-27 07:19:24

graysky
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Re: Haswell Refresh processor running at full speed

Which C-state does it idle in per i7z?


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#5 2014-07-27 22:19:54

Pse
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Registered: 2008-03-15
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Re: Haswell Refresh processor running at full speed

Are Ubuntu and Mint using Intel P-State? If they are not, you can make Arch use whatever power governor they are using for the CPU.

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#6 2014-07-28 01:53:52

Xabre
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Re: Haswell Refresh processor running at full speed

No, Ubuntu disables pstate and still uses ondemand. Am guessing Mint does the same.

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#7 2014-07-28 07:28:36

graysky
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Re: Haswell Refresh processor running at full speed

graysky wrote:

Which C-state does it idle in per i7z?


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#8 2014-07-28 10:33:15

RankoKohime
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Registered: 2014-01-08
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Re: Haswell Refresh processor running at full speed

graysky wrote:
graysky wrote:

Which C-state does it idle in per i7z?

Quite a bit in C7.

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#9 2014-11-04 11:37:13

thearcherblog
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Registered: 2014-10-30
Posts: 165

Re: Haswell Refresh processor running at full speed

I had the same problem before but I disable the intel_pstate at kernel and enable the cpupower powersave so now it's running at 800Mhz and going to 4.4 when need it.

Temperatures are now 15 degrees less XD

Please, let me know if you need more infor about, was a headache for me!

Regards,

TheArcher

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#10 2015-02-20 23:06:32

graysky
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Re: Haswell Refresh processor running at full speed

I found this interesting since my Haswell too experiences it but my Ivybridge does not.  I opened a bug report upstream after collecting some data under Xorg and under a TTY.

The attached png image was generated by booting into Xorg (shown in blue) or into a TTY (shown in green) and then using `i7z -w a` and plotting the resulting frequencies.  You can clearly see the differences.  The top plot is the distribution on the Haswell CPU.  The mean freq at idle under Xorg is 3,401 MHz compared to 1,201 MHz into a text TTY without Xorg on the Haswell.

I also included the same experiment on an Ivybridge CPU.  Here the two mean values are the same.

Distribution_of_CPU_Freq_at_Idle_Under_TTY_or_Xo.jpg


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#11 2015-02-21 11:38:05

graysky
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Re: Haswell Refresh processor running at full speed

I just realized that the i7-4790k is technically a "Haswell Refresh" and after collecting the same data on an older "Haswell" CPU, this bug seems to only affect the "Haswell Refresh" CPUs: the i3-4130T shows nearly the same mean value at idle under either Xorg or a text TTY (mean Xorg=1,089 MHz and mean TTY=1,029 MHz).

@RankoKohime - What chipset is the board you're using with your i7-4790k?

Last edited by graysky (2015-02-21 11:39:34)


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#12 2015-02-24 02:02:38

graysky
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Re: Haswell Refresh processor running at full speed

@op - Is this any help for you: https://bbs.archlinux.org/viewtopic.php … 8#p1505708

???


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#13 2015-03-23 01:25:18

RankoKohime
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Registered: 2014-01-08
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Re: Haswell Refresh processor running at full speed

I just now noticed the more recent responses to this thread.

graysky: I'm using the Z97 chipset, specifically I'm using the AsRock Z97 Extreme6 motherboard.  I'm currently compiling a kernel with the 1000 HZ tick rate set, so we'll see if that effects my situation.

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#14 2015-03-23 08:58:56

graysky
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Re: Haswell Refresh processor running at full speed

It may help but not fix the underlying issue. For these chips, pstates is truely broken and needs to be fixed upstream.  See the bugzilla referenced in the FS I opened, https://bugzilla.kernel.org/show_bug.cgi?id=93521


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