| Notice the almost equal numbers for level1 and level6 interrupt.

Level 6 is usually used for ethernet devices and level 1 is for
soft interrupts.  Since an ethernet interrupt usually results in
scheduling a network soft interrupt, that's the reason why both
counts are very close in value.

| I kept an eye on the display for some time during a kernel build,
| and the maximum difference between these two numbers was less
| than 10.  I also noticed that the "wired count" in the vmstat
| display was very close to the interrupt level1 and level6
| interrupt counters.

wired count is just a coincidence.

Eduardo