Atop command is a tool for monitoring Linux system resources and processes. It is not an internal command and needs to be installed.
[[email protected] ~]# atop -bash: atop: command not found [[email protected] ~]# yum install atop -y #Debian && Ubuntu apt-get install atop #Fedora dnf install atop
Atop records the operation status of the system at a certain frequency. The collected data includes the usage of system resources (CPU, memory, disk and network) and process operation, and can be saved in disk in the form of log file. After the server has a problem, we can obtain the corresponding atop log file for analysis. Atop is an open source software.
atop -w file [-S] [-a] [interval [samples]] atop -r [file] [-b [YYYYMMDD]hhmm] [-e [YYYYMMDD]hhmm] [-flags]
Shortcut keys for process graph
G # default output M # memory related output D # disk related output N # network related output C # command line output U # view the corresponding user resource usage P # displays all information occupancy of each process (disk, MEM, IO) P (uppercase) # regular matching, showing all matched processes Q # exit
[[email protected] ~]# atop ATOP - centos7 2021/03/29 08:33:28 ---------------- 10s elapsed PRC | sys 0.18s | user 0.35s | #proc 95 | #tslpu 0 | #zombie 0 | #exit 0 | CPU | sys 1% | user 3% | irq 0% | idle 96% | wait 0% | ipc notavail | CPL | avg1 0.27 | avg5 0.13 | avg15 0.13 | csw 1088 | intr 954 | numcpu 1 | MEM | tot 972.3M | free 203.3M | cache 563.1M | buff 2.1M | slab 83.8M | hptot 0.0M | SWP | tot 2.0G | free 2.0G | swcac 0.0M | | vmcom 266.0M | vmlim 2.5G | NET | transport | tcpi 1 | tcpo 1 | udpi 1 | udpo 1 | tcpao 0 | NET | network | ipi 17 | ipo 3 | ipfrw 0 | deliv 17 | icmpo 1 | NET | ens33 ---- | pcki 20 | pcko 5 | sp 0 Mbps | si 6 Kbps | so 1 Kbps | PID SYSCPU USRCPU RDELAY VGROW RGROW RDDSK WRDSK ST EXC THR S CPUNR CPU CMD 1/1 18378 0.08s 0.33s 0.11s 0K 0K 0K 0K -- - 3 S 0 4% python3 27620 0.04s 0.02s 0.00s 0K 0K 0K 0K -- - 1 R 0 1% atop 27664 0.04s 0.00s 0.02s 0K 0K 0K 0K -- - 1 S 0 0% kworker/0:1 404 0.02s 0.00s 0.05s 0K 0K 0K 0K -- - 1 R 0 0% xfsaild/dm-0 872 0.00s 0.00s 0.00s 0K 0K 0K 0K -- - 5 S 0 0% tuned 19670 0.00s 0.00s 0.00s 0K 0K 0K 0K -- - 1 S 0 0% sshd 870 0.00s 0.00s 0.00s 0K 0K 0K 0K -- - 3 S 0 0% rsyslogd 1 0.00s 0.00s 0.00s 0K 0K 0K 0K -- - 1 S 0 0% systemd 6 0.00s 0.00s 0.09s 0K 0K 0K 0K -- - 1 S 0 0% ksoftirqd/0 9 0.00s 0.00s 0.29s 0K 0K 0K 0K -- - 1 R 0 0% rcu_sched 26820 0.00s 0.00s 0.00s 0K 0K 0K 0K -- - 1 S 0 0% kworker/0:2
The output information is described in detail below
Atop column: this column displays the host name, information sampling date and time point PRC column: this column displays the overall operation of the process Running time of sys and usr field # processes in kernel state and user state Total number of proc field # processes Number of zombie field # dead processes Exit field #atop the number of processes that exited during the sampling period CPU column: this column displays the usage of the CPU as a whole (that is, the CPU resources of the multi-core CPU as a whole) When sys and usr fields #r are used to process the CPU, the proportion of CPU time occupied by the process in kernel state and user state The IRQ field #q indicates the percentage of time that the CPU is used to process interrupts The idle field #0 indicates the percentage of time the CPU is fully idle The wait field #0 indicates the percentage of time that the CPU is in the state of "CPU idle due to process waiting for disk IO" CPU column: this column displays the CPU usage of a certain core CPL column: this column displays the CPU load Avg1, avg5, and avg15 fields # the average number of processes in the running queue in the past 1 minute, 5 minutes, and 15 minutes Number of CSW field # context exchanges Intr field # interrupt occurrence times MEM column: this column displays the memory usage Tot field # total physical memory Free field # free memory size The cache field # is used for the memory size of the page cache The buff field # is used for the memory size of the file cache The slab field # is the amount of memory occupied by the system kernel SWP column: this column displays the usage of swap space Total tot field # swap area Free field # free swap space size PAG column: this column displays virtual memory paging Swin, swout fields # swap in and swap out memory pages DSK column: this column displays disk usage SDA field # disk device ID Busy field # disk busy time ratio Number of read and write field # read and write requests Net column: displays network status, including transport layer (TCP and UDP), IP layer and active network port information XXXI field # number of packets received by each layer or active network port Xxxo field # number of contracts issued by each layer or active network interface