atop  2.6.0
About: ATOP is an advanced interactive monitor for Linux-systems to view the load on system-level and process-level.
  Fossies Dox: atop-2.6.0.tar.gz  ("unofficial" and yet experimental doxygen-generated source code documentation)  

atop Documentation

Some Fossies usage hints in advance:

  1. To see the Doxygen generated documentation please click on one of the items in the steelblue colored "quick index" bar above or use the side panel at the left which displays a hierarchical tree-like index structure and is adjustable in width.
  2. If you want to search for something by keyword rather than browse for it you can use the client side search facility (using Javascript and DHTML) that provides live searching, i.e. the search results are presented and adapted as you type in the Search input field at the top right.
  3. Doxygen doesn't incorporate all member files but just a definable subset (basically the main project source code files that are written in a supported language). So to search and browse all member files you may visit the Fossies atop-2.6.0.tar.gz contents page and use the Fossies standard member browsing features (also with source code highlighting and additionally with optional code folding).
README
DEPENDENCIES

Install the following packages to be able to build atop (package name
can be different depending on the Linux distro):

* zlib-devel    or libz-dev or zlib1g-dev
* ncurses-devel or libncurses5-dev/libncursesw5-dev


Install the following packages to be able to execute atop (package name
can be different depending on the Linux distro):

* zlib    or zlib1g
* ncurses or libncurses5/libncursesw5


INSTALLING AND USING ATOP

For interactive use, it is sufficient to install ATOP with the command
(as root):

	make systemdinstall

		or

	make sysvinstall

For automatic logging in compressed binary format, see the
description in the manual-page.

The kernel module 'netatop' can be downloaded and installed separately
from www.atoptool.nl/downloadnetatop.php
This module is optional and can be used to gather network statistics
per process/thread as described in www.atoptool.nl/netatop.php


KERNEL ISSUES WITH PROCESS ACCOUNTING
-------------------------------------

Newer upstream kernels (e.g. 4.8 and 4.9) have two issuess
with process accounting:

1) Sometimes process accounting does not work at allĀ¹. Atopacctd tries to
work around this issue, by retrying to initialize process accounting
several times.

2) When using the NETLINK inface, the command TASKSTATS_CMD_GET
consequently returns -EINVALĀ². Atopacctd needs NETLINK to be able to
be triggered that some process in the system has finished. In this way,
atopacctd can be in a blocking state as long as no processes terminate.
When atopacctd detects that NETLINK fails, it switches into a polling
mode to periodically try if it can read process accounting records as
a workaround. This issue has to do with cpumasks and you can work-around
it by building a kernel that has CONFIG_NR_CPUS configured to exactly
the amount of CPUs (logical CPUs) in the system the kernel runs on. You
can find this kernel option under "Processor type and features" -->
"Maximum number of CPUs".


[1] Bug 190271 - process accounting sometimes does not work
https://bugzilla.kernel.org/show_bug.cgi?id=190271

[2] Bug 190711 - Process accounting: Using the NETLINK interface,
the command TASKSTATS_CMD_GET returns -EINVAL
https://bugzilla.kernel.org/show_bug.cgi?id=190711

Linux kernel mailing list thread:

[REGRESSION] Two issues that prevent process accounting (taskstats) from
working correctly
https://lkml.org/lkml/2016/12/19/182


Gerlof Langeveld
gerlof.langeveld@atoptool.nl