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The command "cpupower frequency-info" can be used when using cpupower to
monitor and test processor behaviour to determine if the processor is
behaving as expected. This data can be compared to the output of
/proc/cpuinfo or the output of
/sys/devices/system/cpu/cpuX/cpufreq/scaling_available_frequencies
to determine if the cpu is in an expected state.
When doing this I noticed comparison test failures due to the way the
data is displayed in cpupower. For example,
[root@intel-s3e37-02 cpupower]# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies
2262000 2261000 2128000 1995000 1862000 1729000 1596000 1463000 1330000
1197000 1064000
compared to
[root@intel-s3e37-02 cpupower]# cpupower frequency-info
analyzing CPU 0:
driver: acpi-cpufreq
CPUs which run at the same hardware frequency: 0
CPUs which need to have their frequency coordinated by software: 0
maximum transition latency: 10.0 us.
hardware limits: 1.06 GHz - 2.26 GHz
available frequency steps: 2.26 GHz, 2.26 GHz, 2.13 GHz, 2.00 GHz, 1.86 GHz, 1.73 GHz, 1.60 GHz, 1.46 GHz, 1.33 GHz, 1.20 GHz, 1.06 GHz
available cpufreq governors: conservative, userspace, powersave, ondemand, performance
current policy: frequency should be within 1.06 GHz and 2.26 GHz.
The governor "performance" may decide which speed to use
within this range.
current CPU frequency is 2.26 GHz (asserted by call to hardware).
boost state support:
Supported: yes
Active: yes
shows very different values for the available frequency steps. The cpupower
output rounds off values at 2 decimal points and this causes problems with
test scripts. For example, with the data above,
1.064 is 1.06
1.197 is 1.20
1.596 is 1.60
1.995 is 2.00
2.128 is 2.13
and most confusingly,
2.261 is 2.26
2.262 is 2.26
Truncating these values serves no real purpose other than making the output
pretty. Since the default has been to round off these values I am adding
a -n/--no-rounding option to the cpupower utility that will display the
data without rounding off the still significant digits.
After patch,
analyzing CPU 0:
driver: acpi-cpufreq
CPUs which run at the same hardware frequency: 0
CPUs which need to have their frequency coordinated by software: 0
maximum transition latency: 10.000 us.
hardware limits: 1.064000 GHz - 2.262000 GHz
available frequency steps: 2.262000 GHz, 2.261000 GHz, 2.128000 GHz, 1.995000 GHz, 1.862000 GHz, 1.729000 GHz, 1.596000 GHz, 1.463000 GHz, 1.330000 GHz, 1.197000 GHz, 1.064000 GHz
available cpufreq governors: conservative, userspace, powersave, ondemand, performance
current policy: frequency should be within 1.064000 GHz and 2.262000 GHz.
The governor "performance" may decide which speed to use
within this range.
current CPU frequency is 2.262000 GHz (asserted by call to hardware).
boost state support:
Supported: yes
Active: yes
Acked-by: Thomas Renninger <trenn@suse.de>
Signed-off-by: Prarit Bhargava <prarit@redhat.com>
[rjw: Subject]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Prarit Bhargava
Thomas Renninger
Dominik Brodowski