Top is a dynamic display process where the current state can be refreshed continuously with the user key. If the command is executed in the foreground, it will monopolize the foreground until the user terminates the program. More accurately, the top command provides real-time status monitoring of the system's processor. It will display the most "sensitive" CPU in the system. Task List. This command can be used by CPU. Memory usage and execution time to sort tasks, and many of the features of the command can be set through interactive commands or in personal customization files.
Top-12:38:33 up, 23:15, 7 users, Load average:60.58, 61.14, 61.22
tasks:203 Total, 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 0 627m 209m 207m R 0 11.0 297:14.76 Oracle
4267 Oracle 0 626m 144m 143m R 6 7.6 89:16.62 Oracle
3458 Oracle 0 672m 133m 124m R 0 7.1 1283:08 Oracle
3478 Oracle 0 672m 124m 115m R 0 6.6 1272:30 Oracle
3395 Oracle 0 672m 122m 113m R 0 6.5 1270:03 Oracle
3480 Oracle 0 672m 122m 109m R 8 6.4 1274:13 Oracle
3399 Oracle 0 672m 121m 110m R 0 6.4 1279:37 Oracle
4261 Oracle 0 634m 100m 99m R 0 5.3 86:13.90 Oracle
25737 Oracle 0 632m 81m 74m R 0 4.3 272:35.42 Oracle
7072 Oracle 0 626m 72m 71m R 0 3.8 6:35.68 Oracle
16073 Oracle 0 630m 68m 63m R 8 3.6 175:20.36 Oracle
16140 Oracle 0 630m 66m 60m R 0 3.5 175:13.42 Oracle
16122 Oracle 0 630m 66m 60m R 0 3.5 176:47.73 Oracle
786 Oracle 0 627m 63m 63m R 0 3.4 1:54.93 Oracle
4271 Oracle 0 627m 59m 58m R 8 3.1 86:09.64 Oracle
4273 Oracle 0 627m 57m 56m R 8 3.0 84:38.20 Oracle
22670 Oracle 0 626m 50m 49m R 0 2.7 84:55.82 Oracle
I. Top FIVE ELEMENTS statistics
The first five elements of the statistical information area are the statistical information of the whole system.
1. The first line is the task queue information
Results of execution with uptime command:
[Email protected] ~]# uptime
13:22:30 up 8 min, 4 users, Load average:0.14, 0.38, 0.25
The contents are as follows:
12:38:33 |
Current time |
Up 50days |
System run time, format last: minutes |
1 user |
Number of currently logged on users |
Load average:0.06, 0.60, 0.48 |
System load, which is the average length of the task queue. The three values were 1 minutes, 5 minutes, and 15 minutes ago to the present average. |
2. Second to third behavioral process and CPU information
When there are multiple CPUs, the content may be more than two lines. The contents are as follows:
tasks:29 Total |
Total number of processes |
1 Running |
Number of processes that are running |
Sleeping |
Number of processes for sleep |
0 stopped |
Number of processes stopped |
0 Zombie |
Number of zombie processes |
Cpu (s): 0.3% US |
Percentage of CPU occupied by user space |
1.0% Sy |
Percentage of CPU consumed by kernel space |
0.0% ni |
CPU percentage of processes that have changed priority in user process space |
98.7% ID |
Percentage of idle CPU |
0.0% WA |
Percentage of CPU time waiting for input and output |
3.45th Behavior Memory information.
The contents are as follows:
MEM:191272K Total |
Total Physical Memory |
173656k used |
Total amount of physical memory used |
17616k Free |
Total Free Memory |
22052k buffers |
Amount of memory to use as the kernel cache |
SWAP:192772K Total |
Total Swap Area |
0k used |
Total number of swap areas used |
192772k Free |
Total Free Swap Area |
123988k Cached |
The total amount of buffer swap area. The in-memory content is swapped out to the swap area and then swapped in to 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. |
Two. Process information
Column Name |
Meaning |
Pid |
Process ID |
PPID |
Parent Process ID |
Ruser |
Real User Name |
Uid |
User ID of the process owner |
USER |
User name of the process owner |
GROUP |
Group Name of Process owner |
Tty |
The terminal name of the startup process. Processes that are not started from the terminal are displayed as? |
PR |
Priority level |
NI |
Nice value. Negative values indicate high priority, positive values indicate low priority |
P |
Last CPU used, only meaningful in multi-CPU environment |
%cpu |
CPU time consumption percentage last updated to current |
Time |
Total CPU time used by the process, in seconds |
time+ |
Total CPU time used by the process, Unit 1/100 sec |
%MEM |
Percentage of physical memory used by the process |
VIRT |
The total amount of virtual memory used by the process, in kilobytes. Virt=swap+res |
SWAP |
The size, in kilobytes, of the virtual memory that the process is using, swapped out. |
Res |
The size, in kilobytes, of the physical memory that the process used and was not swapped out. Res=code+data |
CODE |
The amount of physical memory the executable code occupies, in kilobytes |
DATA |
The amount of physical memory that is used by parts other than executable code (data segment + stack), in kilobytes |
Shr |
Shared memory size, in kilobytes |
Nflt |
Number of page faults |
Ndrt |
The number of pages that were modified the last time it was written to. |
S |
Process state. d= non-disruptive sleep state R= Run S= Sleep t= Tracking/Stopping z= Zombie Process |
COMMAND |
Command name/command line |
Wchan |
If the process is sleeping, the system function name in sleep is displayed |
Flags |
Task Flag, reference sched.h |
Linux Top Command parsing