CPU usage of Linux tracking process, memory consumption

This article uses Java processes to illustrate

1. View the CPU usage of the Java process and its threads

First use PS-EF to find the Java process ID

# ps-ef|grep Java

Then use the top-p PID command to view the CPU used by the process, for example:

[[Email protected] ~]# top-p 23386
top-11:10:52 up 124 days, 19:18, 2 users, Load average:0.00, 0.00, 0.00
Tasks:1 Total, 0 running, 1 sleeping, 0 stopped, 0 zombie
Cpu (s): 0.0%us, 0.0%sy, 0.0%ni,100.0%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
mem:16294180k Total, 1601480k used, 14692700k free, 262604k buffers
swap:8191992k Total, 0k used, 8191992k free, 647004k cached

PID USER PR NI VIRT RES SHR S%cpu%MEM time+ COMMAND
23386 Root 0 12.4g 299m 10m S 0.0 1.9 0:56.56 Java

At this point, if you want to see the CPU usage of the thread, manually enter Shift+h (show threads on) to switch the display thread.

We can use a parameter directly to open the thread-occupied CPU tracking by default, using the-h parameter, for example:

[[Email protected] ~]# top-p 23386-h
top-11:07:59 up 124 days, 19:15, 2 users, Load average:0.00, 0.00, 0.00
tasks:185 Total, 0 running, 185 sleeping, 0 stopped, 0 zombie
Cpu (s): 0.0%us, 0.0%sy, 0.0%ni, 99.9%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
mem:16294180k Total, 1601224k used, 14692956k free, 262596k buffers
swap:8191992k Total, 0k used, 8191992k free, 646996k cached

PID USER PR NI VIRT RES SHR S%cpu %MEMtime+COMMAND
23386 Root 0 12.4g 299m 10m S 0.3 1.9 0:00.02 Java
23387 Root 0 12.4g 299m 10m S 0.0 1.9 0:07.63 Java
23388 Root 0 12.4g 299m 10m S 0.0 1.9 0:00.08 Java
23389 Root 0 12.4g 299m 10m S 0.0 1.9 0:00.07 Java
23390 Root 0 12.4g 299m 10m S 0.0 1.9 0:00.08 Java
23391 Root 0 12.4g 299m 10m S 0.0 1.9 0:00.07 Java
23392 Root 0 12.4g 299m 10m S 0.0 1.9 0:00.08 Java
23393 Root 0 12.4g 299m 10m S 0.0 1.9 0:00.08 Java
23394 Root 0 12.4g 299m 10m S 0.0 1.9 0:00.08 Java

Note: Focus on%CPU to see which thread consumes the most CPU and then find the corresponding PID.

The time/time+ of the top command refers to the CPU time used by the process, not the time the process starts up to now, so if a process uses very little CPU, even if the process already exists for n long time, time/time+ is also a small number.

2. View Java Process Memory usage

# Cat/proc/23386/status
Name:java
State:s (sleeping)
Tgid:23386
Pid:23386
Ppid:1
tracerpid:0
uid:0 0 0 0
gid:0 0 0 0
utrace:0
fdsize:256
groups:0
vmpeak:13003444 KB
vmsize:13003444 KB
vmlck:0 KB
vmhwm:311496 KB
vmrss:307048 KB
vmdata:12846208 KB
vmstk:88 KB
Vmexe:32 KB
vmlib:14256 KB
vmpte:1704 KB
vmswap:0 KB
threads:194

Description

vmrss:307048 KB represents the physical memory that is occupied.

threads:194 says 194 threads are currently open altogether.

CPU usage of Linux tracking process, memory consumption