Projects / atop


Atop is an ASCII full-screen performance monitor that is capable of reporting the activity of all processes (even if processes have finished during the interval), daily logging of system and process activity for long-term analysis, highlighting overloaded system resources by using colors, etc. At regular intervals, it shows system-level activity related to the CPU, memory, swap, disks, and network layers, and for every active process it shows the CPU utilization, the memory growth, priority, username, state, and exit code.

Operating Systems

Recent releases

  •  25 Jul 2012 06:42

    Release Notes: This releases adds monitoring of resource consumption for individual threads, improves color handling for overloaded resources, adds selections for multiple system resources like disks and logical volumes, implements handling of arrow keys, applies limitations for process accounting, supports more resources like CPUs, and adds more per-process counters related to memory consumption.

    •  14 Mar 2011 22:08

      Release Notes: An additional value is shown for the current frequency and the current scaling percentage of the CPU. Additional system-level counters are shown for the total number of threads that are running, sleeping interruptible, and sleeping uninterruptible. When the number of lines in a window is too small for the amount of system-level lines, the number of variable resources (like disks, interfaces, etc.) is limited automatically to be able to continue. The signal SIGUSR2 can be sent to atop to take one more sample and terminate (e.g. used to speed up suspend/hibernate). Support for the disk type 'mmcblk'.

      •  03 May 2010 10:30

        Release Notes: Disk I/O statistics are maintained on level of logical volume (LVM) and MD device. Log files are properly switched in case of suspend/hibernate. Layout of lines with system-level statistics can be redefined. Previous atop-versions are automatically activated for older log files.

        •  26 Jan 2010 06:16

          Release Notes: The screen interface has been redesigned completely with support for a variable number of columns depending on the window size. It is now possible to define your own output line with process-level statistics. A system-wide configuration file was introduced for atop and atopsar. Handling of log files was improved and additional counters are maintained.

          •  06 Mar 2008 13:20

            Release Notes: The atop command shows the number of running and sleeping (interruptible/non-interruptible) threads per process and shows the PPID per process. The command atopsar is now able to make summary reports and shows information about the top 3 most active processes per sample. In both commands, several bugs have been fixed.

            Recent comments

            22 Aug 2012 03:31 domperignon

            Really nice tool, I use it to monitor all of my servers

            03 Sep 2002 08:21 robertdb

            great tool!
            atop is a tool, which is not like any others I know. Try it, for it will give you other information about your system then "conventional" tools like top. I use it on our productive systems. At least once a day atop runs on all machines, to observe the difference in processes between two intervals.


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