Linux commands: Top

Today's Test colleague told me that the test environment has been an oom, let me analyze, the first to use the top command, record.

1. First Five Elements information

top-10:58:46 up-Days, 20:22, 3 users, load average:0.15, 0.08, 0.08
tasks:128 Total, 1 running, 127 sleeping, 0 stopped, 0 zombie
%CPU (s): 0.5 us, 0.2 sy, 0.0 ni, 99.2 ID, 0.0 wa, 0.0 hi, 0.0 si, 0.2nd
KiB mem:3684076 Total, 1360600 free, 1077208 used, 1246268 Buff/cache
KiB swap:4194300 Total, 4083556 free, 110744 used. 2347760 Avail Mem

First line: Current time, System run time, connection user, System load: 1 minutes, 5 minutes, 15 minutes

Second line: Total number of processes, number of running, number of sleep processes, stop, zombie process

The third line: the user space as a percentage of CPU, the kernel as a percentage of CPU, the user process space has changed the priority of the process occupied CPU percentage, the Idle CPU percentage, HI is the hardware interrupt waiting for the input and output percentage, SI is the software interrupt CPU percentage, St is the actual CPU time allocated to tasks running on other virtual machines

Row four: Total amount of physical memory, free memory, memory used as the amount of kernel cache

Line five: Total swap area, amount of idle swap, usage, buffer swap total: In-memory content is swapped out to swap, and then swapped into memory, but the used swap area has not been overwritten, which is the size of the swap area where the content already exists in memory . When the corresponding memory is swapped out again, it is no longer necessary to write to the swap area.

2. Process information

PID USER PR NI VIRT RES SHR S%cpu%MEM time+ COMMAND

22677 Root 0 3990944 858676 13168 S 4.0 23.3 5:09.03 java

PID: Process ID User: Customer PR: Priority Ni:nice value negative indicates high priority, positive low priority VIRT: Total amount of virtual memory used by process (KB units) virt=swap+res (swap: Virtual memory used, swapped out size) RES: In Process used, not swapped out of size SHR: Shared memory size, KB S: Progress State (S:sleep r:running t:trace/stop Z: Zombie process D: Non-disruptive sleep state)%CPU:CPU utilization%MEM: Memory Utilization time+ : Total Process run time command: Name/command line

is an extra by the F key can let top display some of the columns, say a few more important data: Use the volume (data area + stack) code: Size swap: Use swap space

Linux commands: Top