The trick is to use vmstat and look at the number for "wait on acknowledge".
vmstat -S m 1 100 |
Look under “cpu” and the “wa” column. If this number is high, it is bad. It should be zero. Some sample output from vmstat looks like this:
procs -----------memory---------- ---swap-- -----io---- -system-- ----cpu---- r b swpd free buff cache si so bi bo in cs us sy id wa 0 0 0 406 83 3062 0 0 1 5 1 4 0 0 99 1 0 0 0 406 83 3062 0 0 0 0 2020 49 0 0 100 0 0 0 0 406 83 3062 0 0 0 0 2020 41 0 0 100 0 0 0 0 406 83 3062 0 0 0 0 2018 53 0 0 100 0 |
Look at the column furthest to the right.