Added cpufreq notes to the knowledge base

knowledge base/cpufreq.md

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+# Cpufreq
+
+Default governor is _ondemand_ for older CPUs and kernels and _schedutil_ for new CPUs and kernels.
+
+## TL;DR
+
+```shell
+# list the available governors
+cpupower frequency-info --governors
+
+# get the current active governor
+cpupower frequency-info --policy
+
+# set a new governor
+sudo cpupower frequency-set --governor performance
+sudo cpupower frequency-set --governor powersave
+sudo cpupower frequency-set --governor schedutil
+```
+
+## Sources
+
+- [CPU frequency scaling]
+- [CPU governer settings ignore nice load]
+
+[cpu frequency scaling]: https://wiki.archlinux.org/title/CPU_frequency_scaling
+[cpu governer settings ignore nice load]: https://forum.manjaro.org/t/cpu-governer-settings-ignore-nice-load/71476/3

knowledge base/set the ondemand cpu governor to not rise the frequencies for niced load.md

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+# Set the _ondemand_ CPU governor to not rise the frequencies for niced loads
+
+## TL:DR
+
+```shell
+sudo cpupower frequency-set --governor ondemand
+echo 1 | sudo tee /sys/devices/system/cpu/cpufreq/ondemand/ignore_nice_load
+
+# set this on boot
+echo "w /sys/devices/system/cpu/cpufreq/ondemand/ignore_nice_load - - - - 1" | sudo tee /etc/tmpfiles.d/ondemand-ignore-nice.conf
+```
+
+## Sources
+
+- [Laptop overheating and battery duration reduction]
+
+[laptop overheating and battery duration reduction]: https://wiki.archlinux.org/?title=BOINC#Laptop_overheating_and_battery_duration_reduction