Public bug reported: == 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 ** Tags added: architecture-ppc64le bugnameltc-149045 severity-high targetmilestone-inin1610 -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1644716 Title: cpufreq-set --freq option is not able to set the specific frequency value To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1644716/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs