There are lots of terminal based real-time system reporting tools such as glances and htop that are prettier than classic top.
However, sometimes you find yourself on systems that don’t have glances or htop installed so you’ve got to use top. These tips will make top’s output a bit more useful.
Show CPU cores individually
The default output for top is to summarize the system load of all cores. Here’s my laptop:
%Cpu(s): 0.4 us, 0.3 sy, 0.0 ni, 99.2 id, 0.0 wa, 0.1 hi, 0.0 si, 0.0 st
You can make top show every core’s current use by pressing 1 while it is open. This transforms the CPU line shown above to this:
top - 15:35:42 up 5:17, 1 user, load average: 0.42, 0.54, 0.68
Tasks: 245 total, 1 running, 244 sleeping, 0 stopped, 0 zombie
%Cpu0 : 0.0 us, 0.7 sy, 0.0 ni, 99.3 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st
%Cpu1 : 0.7 us, 0.0 sy, 0.0 ni, 99.3 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st
%Cpu2 : 0.0 us, 0.0 sy, 0.0 ni, 99.3 id, 0.0 wa, 0.0 hi, 0.7 si, 0.0 st
%Cpu3 : 0.6 us, 3.2 sy, 0.0 ni, 95.5 id, 0.0 wa, 0.6 hi, 0.0 si, 0.0 st
%Cpu4 : 0.0 us, 0.0 sy, 0.0 ni,100.0 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st
%Cpu5 : 0.0 us, 0.0 sy, 0.0 ni,100.0 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st
%Cpu6 : 0.0 us, 0.0 sy, 0.0 ni,100.0 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st
%Cpu7 : 0.7 us, 0.0 sy, 0.0 ni, 99.3 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st
GiB Mem : 15.1 total, 9.9 free, 2.9 used, 2.3 buff/cache
GiB Swap: 0.2 total, 0.2 free, 0.0 used. 11.1 avail Mem
Display use as bars
Even better, you can transform these numbers to bar charts by pressing t:
top - 15:34:09 up 5:15, 1 user, load average: 0.62, 0.62, 0.72
Tasks: 246 total, 1 running, 245 sleeping, 0 stopped, 0 zombie
%Cpu0 : 16.7/3.3 20[|||||||||||
%Cpu1 : 23.5/3.9 27[||||||||||||||
%Cpu2 : 28.8/3.3 32[|||||||||||||||||
%Cpu3 : 7.4/4.7 12[||||||
%Cpu4 : 48.4/3.9 52[||||||||||||||||||||||||||||
%Cpu5 : 13.6/3.2 17[|||||||||
%Cpu6 : 37.1/3.3 40[||||||||||||||||||||||
%Cpu7 : 13.2/4.6 18[|||||||||
GiB Mem : 15.1 total, 9.9 free, 2.9 used, 2.3 buff/cache
GiB Swap: 0.2 total, 0.2 free, 0.0 used. 11.2 avail Mem