How were the weightings in the linux load computation chosen?

This question was migrated from Unix & Linux Stack Exchange because it can be answered on Stack Overflow. Migrated 8 years ago.

In Linux, the load average is said to be on 1min/5min/15min. The formula used by the kernel is actually an Exponential moving average.

If we define cpuload(1) as the first computation of the cpu load 1min, and active() as the function returning the number of process in state "running" or "runnable" on the system, then the formula used by the kernel to compute the nth cpu load 1min is:

enter image description here

cpuload(0) is 0; it is the value stored in memory before the first execution of cpuload().

My question is, how was the weighting 2^{-5.log2(e)/60} chosen? In my opinion, 2^-5/60 would have been better because 1min would have been the half-life of the number of process (because (2^-5/60)¹² = 1/2).

Maybe it's helpful if i post the explicit formula of cpuload(n) in addition to the recursive definition above (right-click to see it in full size):

enter image description here

задан user368507 13 March 2011 в 18:06

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