What I would like to see is for all CPUs/HT-siblings 100-%idle... loadavg is not the right measure here...
I would use the cpuN lines from cat /proc/stat
root@turris:~# cat /proc/stat
cpu 5909064 26936 1697407 210303430 1809247 0 1440728 0 0 0
cpu0 3066461 13859 842812 105338697 943297 0 388277 0 0 0
cpu1 2842603 13077 854595 104964733 865950 0 1052451 0 0 0
intr 1361849891 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 718231763 0 0 111179 22 0 0 0 0 0 0 0 0 0 0 0 0 0 0 20486552 15267694 147090191 0 0 0 0 0 2811330 0 14517374 0 2 2 0 0 0 0 0 0 0 40 0 0 4 0 3 33 0 0 0 0 0 0 0 0 0 0 0 1 0 113784447 140749112
ctxt 1038967495
btime 1647964976
processes 2324144
procs_running 1
procs_blocked 0
softirq 1549519881 0 187760591 164873342 579513036 5016228 0 297775348 214348509 0 100232827
root@turris:~# cat /proc/stat
for that purpose, and I would ignore the governor/power scheduler effects... (or I would try to also add information about the CPUs frequencies, but that gets approximate pretty quickly so I think ignoring that is just fine)...