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  uninterruptible 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  measurement).  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
              beyond 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 commentary 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)