Change your directory to /sys/devices/system/cpu/intel_pstateWe have the max_perf_pct and the min_perf_pct and if we cat these files we can see their values.
system:/sys/devices/system/cpu/intel_pstate # l
total 0
drwxr-xr-x 2 root root 0 Oct 21 18:45 ./
drwxr-xr-x 14 root root 0 Oct 21 18:45 ../
-rw-r--r-- 1 root root 4096 Oct 21 18:45 max_perf_pct
-rw-r--r-- 1 root root 4096 Oct 21 18:45 min_perf_pct
-rw-r--r-- 1 root root 4096 Oct 21 18:45 no_turbo
# cat max_perf_pct
100
# cat min_perf_pct
32
This is the default for a powersave governor which you can gather from running the following command.
# cpupower 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: 0.97 ms.
hardware limits: 1.20 GHz - 3.70 GHz
available cpufreq governors: performance, powersave
current policy: frequency should be within 1.20 GHz and 3.70 GHz.
The governor "powersave" may decide which speed to use
within this range.
current CPU frequency is 3.53 GHz (asserted by call to hardware).
boost state support:
Supported: yes
Active: yes
3500 MHz max turbo 4 active cores
3500 MHz max turbo 3 active cores
3600 MHz max turbo 2 active cores
3700 MHz max turbo 1 active cores
Notice the driver is intel_pstate and the current policy is set to powersave
We want the performance governor. So we will need to change our governor to performance. Execute the following.
Thats good its all at 100% but wait we still are not done. There is another setting for P-States. Its called Performance Bias. From the man page cpupower-set you can read the following about it.
----snip----
Options
--perf-bias, -b
Sets a register on supported Intel processore which allows software to convey its policy for the relative importance of performance versus energy savings to the processor.
The range of valid numbers is 0-15, where 0 is maximum performance and 15 ismaximum energy efficiency.
The processor uses this information in model-specific ways when it must select trade-offs between performance and energy efficiency.
This policy hint does not supersede Processor Performance states (P-states) or CPUIdle power states (C-states), but allows software to have influence where it would otherwise be unable to express a preference.
For example, this setting may tell the hardware how aggressively or conservatively to control frequency in the "turbo range" above the explicitly OS-controlled P-state frequency range.It may also tell the hardware how aggressively it should enter the OS requested C-states.
This option can be applied to individual cores only via the --cpu option, cpupower(1).
Setting the performance bias value on one CPU can modify the setting on related CPUs as well (for example all CPUs on one socket), because of hardware restrictions. Use cpupower -c all info -b to verify.
This options needs the msr kernel driver (CONFIG_X86_MSR) loaded.
----snip----
So lets set our bias to 0 so we can get absolute maximum performance. The default is 8 on openSUSE. Execute the following.
# cpupower frequency-set -g performanceAlso if we cat /sys/devices/system/cpu/intel_pstate/min_perf_pct you will notice that it has changed to 100
# cpupower 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: 0.97 ms.
hardware limits: 1.20 GHz - 3.70 GHz
available cpufreq governors: performance, powersave
current policy: frequency should be within 1.20 GHz and 3.70 GHz.
The governor "performance" may decide which speed to use
within this range.
current CPU frequency is 2.83 GHz (asserted by call to hardware).
boost state support:
Supported: yes
Active: yes
3500 MHz max turbo 4 active cores
3500 MHz max turbo 3 active cores
3600 MHz max turbo 2 active cores
3700 MHz max turbo 1 active cores
Thats good its all at 100% but wait we still are not done. There is another setting for P-States. Its called Performance Bias. From the man page cpupower-set you can read the following about it.
----snip----
Options
--perf-bias, -b
Sets a register on supported Intel processore which allows software to convey its policy for the relative importance of performance versus energy savings to the processor.
The range of valid numbers is 0-15, where 0 is maximum performance and 15 ismaximum energy efficiency.
The processor uses this information in model-specific ways when it must select trade-offs between performance and energy efficiency.
This policy hint does not supersede Processor Performance states (P-states) or CPUIdle power states (C-states), but allows software to have influence where it would otherwise be unable to express a preference.
For example, this setting may tell the hardware how aggressively or conservatively to control frequency in the "turbo range" above the explicitly OS-controlled P-state frequency range.It may also tell the hardware how aggressively it should enter the OS requested C-states.
This option can be applied to individual cores only via the --cpu option, cpupower(1).
Setting the performance bias value on one CPU can modify the setting on related CPUs as well (for example all CPUs on one socket), because of hardware restrictions. Use cpupower -c all info -b to verify.
This options needs the msr kernel driver (CONFIG_X86_MSR) loaded.
----snip----
So lets set our bias to 0 so we can get absolute maximum performance. The default is 8 on openSUSE. Execute the following.
# cpupower set -b 0and to check it.
# cpupower info
analyzing CPU 0:
perf-bias: 0
even though it only shows CPU 0 it applies for all and you can see that by adding the -c all switch before info.
Now you have a system running at full performance with P-States.
Note: This will run the CPU's hot and the fans will kick in full speed all the time. So when your away from your system or don't need full performance you will want to put it back in powersave. I'm not responsible for overheating of your CPU. :-)
