Does nmon capture point in time stats or averages?
Well there are two type of numbers • rates and • absolutes. For an absolute example, free memory is an absolute – nmon just show you how much is memory is free. For a rate example, the network stats are rates, here nmon does the following: • Capture a complete set of counters – these are incremented by the kernel like the number of bytes sent. • then nmon waits the number of seconds you asked • then nmon captures a second set of these counters • then nmon calculates the difference between the two sets and divides by the number of seconds, so everything is per second • this number is then displayed on screen or written to the data file So the rates are the average between the two capture points. As the number of seconds increases the rates get more and more steady but note if you reduce the seconds to just one (the minimum to make sure nmon does not use too much CPU time) you will see lots more peaks and dips in the numbers. “Point in time” numbers would be very misleading as they would
