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COPYRIGHT NOTICE ---------------- For all files that are not marked differently: Copyright Gerlof Langeveld 2007-2021 and licensed under the GPL v2 (or any later version). 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 install (systemd based) or make sysvinstall (System V init based) 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 PROCESS ACCOUNTING WITH PSACCT/ACCT PACKAGE ------------------------------------------- Preferably, process accounting should be handled by the atopacctd daemon which is implicitly installed when installing atop. This daemon takes care that process accounting is only active when at least one atop process is running. Besides, when process accounting is activated, atopacctd takes care that the disk utilization is minimal. See the man page of atopacctd for further details. When the psacct or acct package is installed in parallel with the atop package and you want to enable/start the (ps)acct service for permanent process accounting, take care that the atopacct will be disabled. The atopacct service and the (ps)acct service mutually exclude one another. When the (ps)acct service is enabled, atop automatically uses the process accounting file that is used by this package. See also the section PROCESS ACCOUNTING in the man page of atop. 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 SERVICE ACTIVATION AFTER INSTALLATION ------------------------------------- After the package has been installed, be sure that the related services are activated. To support handling of terminated processes using process accounting, enable the atopacct service: systemctl enable --now atopacct Notice that this service should not be enabled when the package psacct or acct (depends on the Linux distribution) has been installed and enabled. In that case atop uses the daily process accounting file created via that package. To support maintaining daily log files to keep track of long-term analysis information, enable the atop service and the related timer: systemctl enable --now atop systemctl enable --now atop-rotate.timer Gerlof Langeveld gerlof.langeveld@atoptool.nl