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== Comment: #0 - PAVAMAN SUBRAMANIYAM <pavsu...@in.ibm.com> - 2016-11-23
03:27:34 ==
---Problem Description---
cpufreq-set --freq option is not able to set the specific frequency value
Contact Information = pavsu...@in.ibm.com
---uname output---
Linux ltc-garri2 4.8.0-27-generic #29-Ubuntu SMP Thu Oct 20 21:01:16 UTC 2016
ppc64le ppc64le ppc64le GNU/Linux
Machine Type = P8
---Debugger---
A debugger is not configured
---Steps to Reproduce---
Install a P8 Open Power Hardware with Ubuntu 16.10 OS.
Then we are executing cpufreq-set which is a small tool which allows to modify
cpufreq settings.
root@ltc-garri2:~# cpufreq-info -c 0
cpufrequtils 008: cpufreq-info (C) Dominik Brodowski 2004-2009
Report errors and bugs to cpuf...@vger.kernel.org, please.
analyzing CPU 0:
driver: powernv-cpufreq
CPUs which run at the same hardware frequency: 0 1 2 3 4 5 6 7
CPUs which need to have their frequency coordinated by software: 0 1 2 3 4 5
6 7
maximum transition latency: 4294.55 ms.
hardware limits: 2.06 GHz - 4.02 GHz
available frequency steps: 4.02 GHz, 3.99 GHz, 3.96 GHz, 3.92 GHz, 3.89 GHz,
3.86 GHz, 3.82 GHz, 3.79 GHz, 3.76 GHz, 3.72 GHz, 3.69 GHz, 3.66 GHz, 3.62 GHz,
3.59 GHz, 3.56 GHz, 3.52 GHz, 3.49 GHz, 3.46 GHz, 3.42 GHz, 3.39 GHz, 3.36 GHz,
3.33 GHz, 3.29 GHz, 3.26 GHz, 3.23 GHz, 3.19 GHz, 3.16 GHz, 3.13 GHz, 3.09 GHz,
3.06 GHz, 3.03 GHz, 2.99 GHz, 2.96 GHz, 2.93 GHz, 2.89 GHz, 2.86 GHz, 2.83 GHz,
2.79 GHz, 2.76 GHz, 2.73 GHz, 2.69 GHz, 2.66 GHz, 2.63 GHz, 2.59 GHz, 2.56 GHz,
2.53 GHz, 2.49 GHz, 2.46 GHz, 2.43 GHz, 2.39 GHz, 2.36 GHz, 2.33 GHz, 2.29 GHz,
2.26 GHz, 2.23 GHz, 2.19 GHz, 2.16 GHz, 2.13 GHz, 2.09 GHz, 2.06 GHz
available cpufreq governors: conservative, ondemand, userspace, powersave,
performance
current policy: frequency should be within 4.02 GHz and 4.02 GHz.
The governor "userspace" may decide which speed to use
within this range.
current CPU frequency is 4.02 GHz (asserted by call to hardware).
cpufreq stats: 4.02 GHz:100.00%, 3.99 GHz:0.00%, 3.96 GHz:0.00%, 3.92
GHz:0.00%, 3.89 GHz:0.00%, 3.86 GHz:0.00%, 3.82 GHz:0.00%, 3.79 GHz:0.00%, 3.76
GHz:0.00%, 3.72 GHz:0.00%, 3.69 GHz:0.00%, 3.66 GHz:0.00%, 3.62 GHz:0.00%, 3.59
GHz:0.00%, 3.56 GHz:0.00%, 3.52 GHz:0.00%, 3.49 GHz:0.00%, 3.46 GHz:0.00%, 3.42
GHz:0.00%, 3.39 GHz:0.00%, 3.36 GHz:0.00%, 3.33 GHz:0.00%, 3.29 GHz:0.00%, 3.26
GHz:0.00%, 3.23 GHz:0.00%, 3.19 GHz:0.00%, 3.16 GHz:0.00%, 3.13 GHz:0.00%, 3.09
GHz:0.00%, 3.06 GHz:0.00%, 3.03 GHz:0.00%, 2.99 GHz:0.00%, 2.96 GHz:0.00%, 2.93
GHz:0.00%, 2.89 GHz:0.00%, 2.86 GHz:0.00%, 2.83 GHz:0.00%, 2.79 GHz:0.00%, 2.76
GHz:0.00%, 2.73 GHz:0.00%, 2.69 GHz:0.00%, 2.66 GHz:0.00%, 2.63 GHz:0.00%, 2.59
GHz:0.00%, 2.56 GHz:0.00%, 2.53 GHz:0.00%, 2.49 GHz:0.00%, 2.46 GHz:0.00%, 2.43
GHz:0.00%, 2.39 GHz:0.00%, 2.36 GHz:0.00%, 2.33 GHz:0.00%, 2.29 GHz:0.00%, 2.26
GHz:0.00%, 2.23 GHz:0.00%, 2.19 GHz:0.00%, 2.16 GHz:0.00%, 2.13 GHz:0.00%, 2.09
GHz:0.00%, 2.06 GHz:0.00% (12)
Then try to set the specific frequency to be set for cpu0.
root@ltc-garri2:~# cpufreq-set -c 0 --freq 3.92GHz
root@ltc-garri2:~# echo $?
0
root@ltc-garri2:~# cat /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_nominal_freq
3258000
root@ltc-garri2:~# cat /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_min_freq
2061000
root@ltc-garri2:~# cat /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_max_freq
4023000
root@ltc-garri2:~# cat /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_cur_freq
4023000
As can be seen the new frequency value is not getting set.
The /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_cur_freq value still shows
4023000 or 4.02GHz but we tried to set 3.92GHz.
Stack trace output:
no
Oops output:
no
Userspace tool common name: /usr/bin/cpufreq-set
Userspace rpm: cpufrequtils
The userspace tool has the following bit modes: 64-bit
System Dump Info:
The system is not configured to capture a system dump.
Userspace tool obtained from project website: na
*Additional Instructions for pavsu...@in.ibm.com:
-Post a private note with access information to the machine that the bug is
occuring on.
-Attach sysctl -a output output to the bug.
-Attach ltrace and strace of userspace application.
== Comment: #2 - SEETEENA THOUFEEK <sthou...@in.ibm.com> - 2016-11-23 03:47:40
==
Screening the issue.
== Comment: #11 - Akshay Adiga <aksad...@in.ibm.com> - 2016-11-23 10:31:56 ==
Pavaman,
I figured out that this is not a cpufrequtils bug but this is because of
way cpufreqd sets a profile.
1) It sets min, max and governor. No other tools is doing so. Hence if we try
to change frequency policies with any tool, the scaling_min_freq still remains
unchanged.
2) On installing cpufreqd, a init script /etc/init.d/cpufreqd is added , which
will over-ride the default governor
set by kernel ( which is ondemand)
You right the scaling_min_freq is being written by init scripts
/etc/init.d/cpufreqd , which loads the cpufreqd (daemon) based on the
configuration file ( /etc/cpufreq.conf)
/etc/cpufreq.conf tells cpufreqd to set both min and max to 100%.
[Profile]
name=Performance High
minfreq=100%
maxfreq=100%
policy=performance
#exec_post=echo 8 > /proc/acpi/sony/brightness
[/Profile]
As such cpufreqd is totally out of sync with the developements in the
community and still relies on the acpi provided sensors to make the
decision ( These are mentioned in .conf under [Rules]) . But as we donot
have any of the files which it looks for, it falls back to set the first
profile mentioned in the cpufreqd.conf .
To fix this issue, we change the configuration to set minfreq=0% , profile will
look like this :
[Profile]
name=Performance High
minfreq=0%
maxfreq=100%
policy=performance
#exec_post=echo 8 > /proc/acpi/sony/brightness
[/Profile]
== Comment: #15 - Akshay Adiga <aksad...@in.ibm.com> - 2016-11-23
23:23:11 ==
** Affects: linux (Ubuntu)
Importance: Undecided
Assignee: Taco Screen team (taco-screen-team)
Status: New
** Tags: architecture-ppc64le bugnameltc-149045 severity-high
targetmilestone-inin1610
--
cpufreq-set --freq option is not able to set the specific frequency value
https://bugs.launchpad.net/bugs/1644716
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