I'm aware this question has been asked numerous times over but unfortunately none of the given answers seem to work for what I need.
Everyone seems to recommend /proc/stat however I can't seem to find 1 answer that works as expected:
as you can see here, core 0 reports being 16% used even though it's actually only 3% used in fact it doesn't matter if it's 100%, it still reports 16% with only a 0.01%-0.02% increase
I've also tested another approach with only $2+$4 +$5 rather than the whole range, but even that returned inaccurate results...
How do CPU monitors, like the graph above, derive their information??
because it doesn't appear to be through /proc/stat unless everyone's doing something wrong.
notable resources:
- Accurate calculation of CPU usage given in percentage in Linux?
- How to get overall CPU usage (e.g. 57%) on Linux
- https://devbest.com/threads/linux-scripting-with-xfce4-panels-generic-monitor-applet.89845/
I've looked through much more, but they all pretty much point to the same things.
As for the script, I know it's a bit messy, I don't work with bash much, but here it is:
#!/bin/bash H=($(awk '/MHz/{printf "%.2fGHz|", $4/1000}' /proc/cpuinfo)) A=($(awk 'FNR>1 && FNR<4 { i=$5+$6; printf "%d|%d\n", i, i+$2+$3+$4+$7+$8+$9 }' /proc/stat)) sleep 0.125 awk -v a="${A[*]}" -v h="${H[*]}" -v n="0" 'FNR>1 && FNR<4 { n++ split(h,s,"|"); split(a,p,"|") i=$5+$6; t=(i+$2+$3+$4+$7+$8+$9)-p[n,1] printf "%s: %s %.2f%\n", $1, s[n], ((t-(i-p[n,0]))/t)*100 }' /proc/stat pretty much all of it was followed from other answers...
If there's a better way to do any of this (such as merging cpuinfo with stat, or not needlessly splitting an array to prevent s[n] from reporting a scalar error, or even sleeping and re-reading within awk), by all means please improve. :)
p[n,1]andp[n,0]?pis a split array fromA:split(a,p,"|"), where the result is basically( idle, total ), check the python source from the first notable resource for more info. ;)split()(it threw me off as well), here's it's equivalent in pythonp = tuple( v.split("|") for v in a )or in other words( "idle|total", ... ) -> ( ( idle, total ), ... )split(a,p,"|")after there will bea[1],a[2]...but nota[1,1]unless you explicitly define it which I can't see you doing.a[1]is"idle|total"(or at least it should be, where bash doesn't agree), which I've already tried every way I could think of to createAas a 2D array, and I can't find anything on creating 2D arrays, or what's even worse is you can't even accessa[n]because that thinksais a scalar.