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ondemand, userspace power governors not available
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krotuss
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Joined: 01 Aug 2008
Posts: 161

PostPosted: Sun Apr 24, 2016 5:11 pm    Post subject: ondemand, userspace power governors not available Reply with quote

Hi, ondemand and userspace power governors are not available on my system, even though they are enabled in kernel confiig..
Code:

uname -a
Linux gentoo 4.4.6-gentoo #4 SMP PREEMPT Sun Apr 24 18:37:20 CEST 2016 x86_64 Intel(R) Core(TM) i5-6500 CPU @ 3.20GHz GenuineIntel GNU/Linux

cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_governors
performance powersave

cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_driver
intel_pstate

grep CONFIG_CPU_FREQ_GOV /usr/src/linux/.config
CONFIG_CPU_FREQ_GOV_COMMON=y
CONFIG_CPU_FREQ_GOV_PERFORMANCE=y
CONFIG_CPU_FREQ_GOV_POWERSAVE=y
CONFIG_CPU_FREQ_GOV_USERSPACE=y
CONFIG_CPU_FREQ_GOV_ONDEMAND=y
CONFIG_CPU_FREQ_GOV_CONSERVATIVE=y


Why is it so and how can I fix it? Thanks.
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Ant P.
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Joined: 18 Apr 2009
Posts: 6014

PostPosted: Sun Apr 24, 2016 5:35 pm    Post subject: Reply with quote

They're not supported or needed on that CPU, setting it to performance is effectively what ondemand would be. intel_pstate works a lot different to other cpufreq drivers (the CPU itself knows how much load it has), so it doesn't make sense to try and control it in software.
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krotuss
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Joined: 01 Aug 2008
Posts: 161

PostPosted: Sun Apr 24, 2016 9:29 pm    Post subject: Reply with quote

Thanks, I assume that this is some recent (4.4?) change in kernel, because when I was, not so long time ago, setting up the box those governors were working.
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Polyatomic
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Joined: 18 May 2014
Posts: 36

PostPosted: Mon Apr 25, 2016 12:04 pm    Post subject: Reply with quote

krotuss wrote:
Thanks, I assume that this is some recent (4.4?) change in kernel, because when I was, not so long time ago, setting up the box those governors were working.

I dunno man! check this out from the Docs in the kernel: intel-pstate.txt
Code:
For contemporary Intel processors, the frequency is controlled by the
processor itself and the P-State exposed to software is related to
performance levels.  The idea that frequency can be set to a single
frequency is fictional for Intel Core processors. Even if the scaling
driver selects a single P-State, the actual frequency the processor
will run at is selected by the processor itself.


I think these docs are relevant to your cpu, maybe the other box had a different
processor?.
Take it easy man! and maybe I'll see ya round.
Code:
root@milton:/sources/linux-stable/Documentation/cpu-freq# cpupower --cpu all frequency-info
analyzing CPU 0:
  driver: intel_pstate
  CPUs which run at the same hardware frequency: 0
  CPUs which need to have their frequency coordinated by software: 0
  maximum transition latency:  Cannot determine or is not supported.
  hardware limits: 1.20 GHz - 3.20 GHz
  available cpufreq governors: performance powersave
  current policy: frequency should be within 1.20 GHz and 3.20 GHz.
                  The governor "powersave" may decide which speed to use
                  within this range.
  current CPU frequency: 1.20 GHz (asserted by call to hardware)
  boost state support:
    Supported: yes
    Active: yes
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Astronome
Tux's lil' helper
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Joined: 02 Jan 2016
Posts: 148

PostPosted: Sun Jun 12, 2016 6:50 pm    Post subject: Reply with quote

Also see http://www.phoronix.com/scan.php?page=news_item&px=MTM3NDQ.
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kernelOfTruth
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Joined: 20 Dec 2005
Posts: 6111
Location: Vienna, Austria; Germany; hello world :)

PostPosted: Mon Jun 13, 2016 9:22 pm    Post subject: Reply with quote

you can append

Code:
intel_pstate=disable


to your bootloader (grub, etc.)


and then set the governor via e.g.

Code:
cpupower frequency-set -g performance


Code:
cpupower frequency-set -g ondemand



running on 4.6.2 ondemand is broken for me (Haswell CPU), frequency stays at lowest level, even with high load (800%),

so I'm currently using the performance governor.


There is (or was) a regression with pstate driver on 4.7 which lead to worse performance compared to ondemand governor,

so if you run into performance and smoothness issues it would be advisable to compare pstate against "old" cpu governor behavior
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toralf
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Joined: 01 Feb 2004
Posts: 3723
Location: Hamburg

PostPosted: Mon Jun 13, 2016 11:15 pm    Post subject: Reply with quote

FWIW "pstate" had have a lot of nasty bugs in the past, whilst ondemand worked fine for years.
OTOH since a while pstate works fine here for my i5 :

Linux t44 4.5.7-hardened-r1 #1 SMP Sun Jun 12 22:08:30 CEST 2016 x86_64 Intel(R) Core(TM) i5-4300U CPU @ 1.90GHz GenuineIntel GNU/Linux
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