Manual: loads.bt

loads.bt(8)					   System Manager's Manual					 loads.bt(8)

NAME
       loads.bt - Prints load averages. Uses bpftrace/eBPF.

SYNOPSIS
       loads.bt

DESCRIPTION
       These  are the same load averages printed by "uptime", but to three decimal places instead of two (not that it really
       matters). This is really a demonstration of fetching and processing a kernel structure from bpftrace.

       Since this uses BPF, only the root user can use this tool.

REQUIREMENTS
       CONFIG_BPF and bpftrace.

EXAMPLES
       Print system load averages every second:
	      # loads.bt

FIELDS
       HH:MM:SS
	      Each output line includes time of printing in "HH:MM:SS" format.

       load averages:
	      These are exponentially-damped moving sum averages of the system loads.  Load is a measurement  of  demand  on
	      system  resources, which include CPUs and other resources that are accessed with the kernel in an uninterrupt‐
	      ible state (TASK_UNINTERRUPTIBLE), which includes types of disk I/O and lock accesses.   Linux  load  averages
	      originally  reflected  CPU  demand only, as it does in other OSes, but this was changed in Linux 0.99.14. This
	      demand measurement reflects not just the utilized resource, but also the queued demand (a saturation  measure‐
	      ment).  Finally, the three numbers are called the "one-", "five-", and "fifteen-minute" load averages, however
	      these times are constants used in the exponentially-damping equation, and the load averages reflect  load	 be‐
	      yond  these  times.  Were you expecting an accurate description of load averages in the man page of a bpftrace
	      tool?

OVERHEAD
       Other than bpftrace startup time, negligible.

SOURCE
       This is from bpftrace.

	      https://github.com/bpftrace/bpftrace

       Also look in the bpftrace distribution for a companion _examples.txt file containing example usage, output, and	com‐
       mentary for this tool.

REFERENCE
       For more on load averages, see:

       http://www.brendangregg.com/blog/2017-08-08/linux-load-averages.html

OS
       Linux

STABILITY
       Unstable - in development.

AUTHOR
       Brendan Gregg

SEE ALSO
       uptime(1)

USER COMMANDS						 2018-09-10						 loads.bt(8)