Linux Top commands (1)

Linux Top commands (1)

TOP is a dynamic display process. You can press the buttons to refresh the current status. if you execute this command on the foreground, it excludes the foreground until the user terminates the program. more accurately, the top command provides real-time monitoring of the status of the system processor. it displays the list of CPU-sensitive tasks in the system. this command can be used by CPU. the memory usage and execution time are used to sort tasks. Many features of this command can be set through interactive commands or in a custom file.

 
 

  
  
top - 12:38:33 up 50 days, 23:15, 7 users, load average: 60.58, 61.14, 61.22  
  
  
Tasks: 203 total, 60 running, 139 sleeping, 4 stopped, 0 zombie  
  
  
Cpu(s) : 27.0%us, 73.0%sy, 0.0%ni, 0.0%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st  
  
  
Mem: 1939780k total, 1375280k used, 564500k free, 109680k buffers  
  
  
Swap: 4401800k total, 497456k used, 3904344k free, 848712k cached  
  
  
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND  
  
  
4338 oracle 25 0 627m 209m 207m R 0 11.0 297:14.76 oracle  
  
  
4267 oracle 25 0 626m 144m 143m R 6 7.6 89:16.62 oracle  
  
  
3458 oracle 25 0 672m 133m 124m R 0 7.1 1283:08 oracle  
  
  
3478 oracle 25 0 672m 124m 115m R 0 6.6 1272:30 oracle  
  
  
3395 oracle 25 0 672m 122m 113m R 0 6.5 1270:03 oracle  
  
  
3480 oracle 25 0 672m 122m 109m R 8 6.4 1274:13 oracle  
  
  
3399 oracle 25 0 672m 121m 110m R 0 6.4 1279:37 oracle  
  
  
4261 oracle 25 0 634m 100m 99m R 0 5.3 86:13.90 oracle  
  
  
25737 oracle 25 0 632m 81m 74m R 0 4.3 272:35.42 oracle  
  
  
7072 oracle 25 0 626m 72m 71m R 0 3.8 6:35.68 oracle  
  
  
16073 oracle 25 0 630m 68m 63m R 8 3.6 175:20.36 oracle  
  
  
16140 oracle 25 0 630m 66m 60m R 0 3.5 175:13.42 oracle  
  
  
16122 oracle 25 0 630m 66m 60m R 0 3.5 176:47.73 oracle  
  
  
786 oracle 25 0 627m 63m 63m R 0 3.4 1:54.93 oracle  
  
  
4271 oracle 25 0 627m 59m 58m R 8 3.1 86:09.64 oracle  
  
  
4273 oracle 25 0 627m 57m 56m R 8 3.0 84:38.20 oracle  
  
  
22670 oracle 25 0 626m 50m 49m R 0 2.7 84:55.82 oracle 
 
 

I. TOP five rows of statistics

The first five lines in the statistical information area are the overall statistical information of the system.

1. The first line is the task queue information.

Same as the execution result of the uptime command:

[Root @ localhost ~] # Uptime

13:22:30 up 8 min, 4 users, load average: 0.14, 0.38, 0.25

The content is as follows:

12:38:33	Current Time
Up 50 days	System running time, in the format of minutes
1 user	Current Login User count
Load average: 0.06, 0.60, 0.48	System load, that is, the average length of the task queue. The three values are the average values from 1 minute, 5 minutes, and 15 minutes ago to the present.

2. Information of the second and third behavior processes and CPU

When multiple CPUs exist, the content may exceed two rows. The content is as follows:

Tasks: 29 total	Process count
1 running	Number of Running Processes
28 sleeping	Number of sleep Processes
0 stopped	Number of stopped Processes
0 zombie	Number of zombie Processes
Cpu (s): 0.3% us	CPU usage percentage of user space
1.0% sy	CPU usage of kernel space
0.0% ni	CPU usage percentage of processes that have changed their priorities in the process space
98.7% id	Idle CPU percentage
0.0% wa	Percentage of CPU time waiting for Input and Output
0.0% hi
0.0% si

3. The memory information of the behavior in the 4th and 5th sections.

The content is as follows:

Mem: 191272 k total	Total physical memory
173656 k used	Total physical memory used
17616 k free	Total idle memory
22052 k buffers	Memory Used as kernel Cache
Swap: 192772 k total	Total number of swap Areas
0 k used	Total number of swap zones used
192772 k free	Total number of idle swap Areas
123988 k cached	The total number of buffer swap areas. The content in the memory is swapped out to the swap zone and then into the memory, but the used swap zone has not been overwritten. This value is the size of the SWAp zone where the content already exists. When the corresponding memory is swapped out again, you do not have to write data to the swap zone.