Linux Systems view several commands for CPU usage __linux

In Linux system maintenance, you may need to review CPU usage frequently and analyze the overall operation of the system. The performance of the monitoring CPU typically includes the following 3 points: Run queues, CPU usage, and context switching.

The best way to run a queue for each CPU is not to exceed 3, for example, if the dual-core CPU is not more than 6. If the queue stays above 3 for a long time, it means that no one process can get a CPU response immediately, and you may need to consider upgrading the CPU. In addition the full load running CPU usage is best is the user space to keep in 65%~70%,system space to keep in 30%, idle keep in 0%~5%.

Below is a summary of several commands commonly used to view CPU usage. 1, top

This command is very common, in the third line shows the current CPU usage.

[root@li676-235 ~]# top-bn 1-i-C
top-14:19:51 up 138, 7:15, 1 user, load average:0.20, 0.33, 0.39
Tasks : Total, 1 running, 114 sleeping, 0 stopped, 0 zombie
Cpu (s): 4.5%us, 3.8%sy, 0.0%ni, 91.0%id, 0.6%wa, 0.0%hi, 0.0 %si, 0.0%st
mem:1014660k Total, 880512k used, 134148k free, 264904k buffers
swap:262140k Total, 34788k used, 227 352k free, 217144k cached
PID USER PR NI virt RES SHR S%cpu%mem time+ COMMAND 
12760 root 0 15084 1944 1632 R 2.0 0.2 0:00.01 top-bn 1-i-C

As shown above, the top command can see the overall system running state and CPU usage.

%us: Indicates the CPU usage of the User space program (not through the Nice Dispatch)

%sy: Represents the CPU usage of the system space, mainly the kernel program.

%ni: CPU Usage for programs that represent user space and pass through the nice tune.

%id: Idle CPU

%wa:cpu time to wait io at runtime

%HI:CPU handle the number of hard interrupts

Number of%si:cpu handling soft interrupts

%st: CPU stolen by Virtual machine 2, Vmstat

Previously in this blog has introduced the use of Vmstat, detailed use and parameter Introduction reference site: http://www.sijitao.net/1925.html.

[root@li676-235 ~]# vmstat 1 5
procs-----------memory-------------Swap-------io------System-------CPU-----
 r b swpd free buff cache si so bi bo in CS us sy ID WA St
 2 0 34792 68376 147688 356132 16 16 421 385 2 2 5 4  1 0
 3 0 34792 97368 147688 326884 0 0 0 0 134 6 0 0 1 0 34792 62432 147696 360704 0 0 0 88 267 278 63
 19 0 0