Thanks for sharing. This article makes load averages make so much more sense.

Thanks for sharing. This article makes load averages make so much more sense.

Originally shared by Thorsten Leemhuis

"[…] Load averages are an industry-critical metric – my company spends millions auto-scaling cloud instances based on them and other metrics – but on Linux there's some mystery around them. Linux load averages track not just runnable tasks, but also tasks in the uninterruptible sleep state. Why? I've never seen an explanation. In this post I'll solve this mystery, and summarize load averages as a reference for everyone trying to interpret them. […] As a set of three, you can tell if load is increasing or decreasing, which is useful. […] History […] The original load averages show only CPU demand […] The Three Numbers […] These three numbers are the 1, 5, and 15 minute load averages. Except they aren't really averages, and they aren't 1, 5, and 15 minutes. […] Linux Uninterruptible Tasks […] When load averages first appeared in Linux, they reflected CPU demand, as with other operating systems. But later on Linux changed them to include not only runnable tasks, but also tasks in the uninterruptible state […] Why? Why, exactly, did Linux do this? […] The origin of uninterruptible […] Fortunately, I did finally find the change, in a compressed mailbox file from 1993 on oldlinux.org. […] Uninterruptible today […] Measuring uninterruptible tasks […] Making sense of Linux load averages […] Load averages measured in a modern tool […] Better Metrics v[…] I'll finish by quoting from a comment at the top of kernel/sched/loadavg.c in the Linux source, by scheduler maintainer Peter Zijlstra:
* This file contains the magic bits required to compute the global loadavg
* figure. Its a silly number but people think its important. We go through
* great pains to make it work on big machines and tickless kernels. […]"
http://www.brendangregg.com/blog/2017-08-08/linux-load-averages.html

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