Load Average: WHAT IS IT????
Those three little numbers tucked away innocently in certain UNIX commands are not so trivial after all. The first point is that load in this context refers to run-queue length (i.e., the sum of the number of processes waiting in the run-queue plus the number currently executing). Therefore, the number is absolute (not relative) and thus it can be unbounded; unlike utilization (AKA ``load'' in queueing theory parlence).
More formally, the UNIX load average is an exponentially smoothed moving average function. In this way sudden changes can be damped so that they don't contribute significantly to the longer term picture.
On average, the UNIX load average metrics are certainly not your average average.
More info can be found in this excellent writing about "Unix Load Average" by Dr. Neil Gunther at
http://www.teamquest.com/resources/gunther/ldavg1.shtml
Posted by zeeky at
11:56 PM
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