[Bug 220117] cpufreq performance governor doesn't correctly apply in combination with isolcpus

[bugzilla-daemon@kernel.org]

https://bugzilla.kernel.org/show_bug.cgi?id=220117

Doug Smythies (dsmythies@telus.net) changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |dsmythies@telus.net

--- Comment #1 from Doug Smythies (dsmythies@telus.net) ---
Depending on the CPU frequency scaling driver, yes listed stale frequencies
might just be the current value for scaling_min_freq. If the processor is idle
and has been for awhile the CPU frequency is considered to be "stale" and a
default value is listed.

Here is an example for my test computer with an Intel i5-10600K processor, with
CPUs 2 and 3 isolated (which isn't actually relevant):

doug@s19:~$ grep . /sys/devices/system/cpu/cpu*/cpufreq/scaling_driver
/sys/devices/system/cpu/cpu0/cpufreq/scaling_driver:intel_pstate
/sys/devices/system/cpu/cpu10/cpufreq/scaling_driver:intel_pstate
/sys/devices/system/cpu/cpu11/cpufreq/scaling_driver:intel_pstate
/sys/devices/system/cpu/cpu1/cpufreq/scaling_driver:intel_pstate
/sys/devices/system/cpu/cpu2/cpufreq/scaling_driver:intel_pstate
/sys/devices/system/cpu/cpu3/cpufreq/scaling_driver:intel_pstate
/sys/devices/system/cpu/cpu4/cpufreq/scaling_driver:intel_pstate
/sys/devices/system/cpu/cpu5/cpufreq/scaling_driver:intel_pstate
/sys/devices/system/cpu/cpu6/cpufreq/scaling_driver:intel_pstate
/sys/devices/system/cpu/cpu7/cpufreq/scaling_driver:intel_pstate
/sys/devices/system/cpu/cpu8/cpufreq/scaling_driver:intel_pstate
/sys/devices/system/cpu/cpu9/cpufreq/scaling_driver:intel_pstate
doug@s19:~$ grep . /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor
/sys/devices/system/cpu/cpu0/cpufreq/scaling_governor:performance
/sys/devices/system/cpu/cpu10/cpufreq/scaling_governor:performance
/sys/devices/system/cpu/cpu11/cpufreq/scaling_governor:performance
/sys/devices/system/cpu/cpu1/cpufreq/scaling_governor:performance
/sys/devices/system/cpu/cpu2/cpufreq/scaling_governor:performance
/sys/devices/system/cpu/cpu3/cpufreq/scaling_governor:performance
/sys/devices/system/cpu/cpu4/cpufreq/scaling_governor:performance
/sys/devices/system/cpu/cpu5/cpufreq/scaling_governor:performance
/sys/devices/system/cpu/cpu6/cpufreq/scaling_governor:performance
/sys/devices/system/cpu/cpu7/cpufreq/scaling_governor:performance
/sys/devices/system/cpu/cpu8/cpufreq/scaling_governor:performance
/sys/devices/system/cpu/cpu9/cpufreq/scaling_governor:performance
doug@s19:~$ grep MHz /proc/cpuinfo
cpu MHz         : 800.000
cpu MHz         : 800.000
cpu MHz         : 800.000
cpu MHz         : 800.000
cpu MHz         : 800.000
cpu MHz         : 800.000
cpu MHz         : 800.000
cpu MHz         : 800.000
cpu MHz         : 800.000
cpu MHz         : 800.000
cpu MHz         : 800.000
cpu MHz         : 800.000

My test computer is extremely idle and all cpu frequencies were stale.
Now, adding a load to isolated CPU 2 gives:

doug@s19:~$ grep MHz /proc/cpuinfo
cpu MHz         : 800.000
cpu MHz         : 800.000
cpu MHz         : 4799.997
cpu MHz         : 800.000
cpu MHz         : 4800.906
cpu MHz         : 4800.362
cpu MHz         : 800.000
cpu MHz         : 800.000
cpu MHz         : 800.000
cpu MHz         : 800.000
cpu MHz         : 4800.017
cpu MHz         : 800.000

-- 
You may reply to this email to add a comment.

You are receiving this mail because:
You are the assignee for the bug.