OK, now I know what you are looking at.
First, yes-- top shows the kernel usage--it shows everything.
If you are watching CPU monitor during a compile and you are looking at the list of items in top. It appears as though the processes are not doing much and certainly don't add up to what the CPU monitor is showing.
However if you look at the top of 'top'-- on the second line of header info, you will see something like--
CPU usage: 6.1% user, 10.6% sys, 83.3% idle
When you are compiling or doing anything that uses the CPU you will notice that 'user' and 'system' added together will equal what CPU monitor displays (or be pretty close)i.e. it well be maxed out. Again synchronization between the two may not be precise.
So even though the individual list of items in top don't seem to add up, there can be many more that don't appear because they are below the screen. Using the -u flag with top will sort by CPU usage with the big CPU usage listed first. Interestingly , that puts top at the top on my work system.
For other top options, type 'man top' in a terminal window.