IBM REDP-4285-00 User Manual
Chapter 2. Monitoring and benchmark tools
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Draft Document for Review May 4, 2007 11:35 am
4285ch02.fm
2.3 Monitoring tools
In this section, we discuss the monitoring tools. Most of the tools come with Enterprise Linux
distributions. You should be familiar with the tools for better understanding of system behavior
and performance tuning.
distributions. You should be familiar with the tools for better understanding of system behavior
and performance tuning.
2.3.1 top
The top command shows actual process activity. By default, it displays the most
CPU-intensive tasks running on the server and updates the list every five seconds. You can
sort the processes by PID (numerically), age (newest first), time (cumulative time), and
resident memory usage and time (time the process has occupied the CPU since startup).
CPU-intensive tasks running on the server and updates the list every five seconds. You can
sort the processes by PID (numerically), age (newest first), time (cumulative time), and
resident memory usage and time (time the process has occupied the CPU since startup).
Example 2-1 Example output from the top command
top - 02:06:59 up 4 days, 17:14, 2 users, load average: 0.00, 0.00, 0.00
Tasks: 62 total, 1 running, 61 sleeping, 0 stopped, 0 zombie
Cpu(s): 0.2% us, 0.3% sy, 0.0% ni, 97.8% id, 1.7% wa, 0.0% hi, 0.0% si
Mem: 515144k total, 317624k used, 197520k free, 66068k buffers
Swap: 1048120k total, 12k used, 1048108k free, 179632k cached
Tasks: 62 total, 1 running, 61 sleeping, 0 stopped, 0 zombie
Cpu(s): 0.2% us, 0.3% sy, 0.0% ni, 97.8% id, 1.7% wa, 0.0% hi, 0.0% si
Mem: 515144k total, 317624k used, 197520k free, 66068k buffers
Swap: 1048120k total, 12k used, 1048108k free, 179632k cached
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
13737 root 17 0 1760 896 1540 R 0.7 0.2 0:00.05 top
238 root 5 -10 0 0 0 S 0.3 0.0 0:01.56 reiserfs/0
1 root 16 0 588 240 444 S 0.0 0.0 0:05.70 init
2 root RT 0 0 0 0 S 0.0 0.0 0:00.00 migration/0
3 root 34 19 0 0 0 S 0.0 0.0 0:00.00 ksoftirqd/0
4 root RT 0 0 0 0 S 0.0 0.0 0:00.00 migration/1
5 root 34 19 0 0 0 S 0.0 0.0 0:00.00 ksoftirqd/1
6 root 5 -10 0 0 0 S 0.0 0.0 0:00.02 events/0
7 root 5 -10 0 0 0 S 0.0 0.0 0:00.00 events/1
8 root 5 -10 0 0 0 S 0.0 0.0 0:00.09 kblockd/0
9 root 5 -10 0 0 0 S 0.0 0.0 0:00.01 kblockd/1
10 root 15 0 0 0 0 S 0.0 0.0 0:00.00 kirqd
13 root 5 -10 0 0 0 S 0.0 0.0 0:00.02 khelper/0
14 root 16 0 0 0 0 S 0.0 0.0 0:00.45 pdflush
16 root 15 0 0 0 0 S 0.0 0.0 0:00.61 kswapd0
17 root 13 -10 0 0 0 S 0.0 0.0 0:00.00 aio/0
18 root 13 -10 0 0 0 S 0.0 0.0 0:00.00 aio/1
13737 root 17 0 1760 896 1540 R 0.7 0.2 0:00.05 top
238 root 5 -10 0 0 0 S 0.3 0.0 0:01.56 reiserfs/0
1 root 16 0 588 240 444 S 0.0 0.0 0:05.70 init
2 root RT 0 0 0 0 S 0.0 0.0 0:00.00 migration/0
3 root 34 19 0 0 0 S 0.0 0.0 0:00.00 ksoftirqd/0
4 root RT 0 0 0 0 S 0.0 0.0 0:00.00 migration/1
5 root 34 19 0 0 0 S 0.0 0.0 0:00.00 ksoftirqd/1
6 root 5 -10 0 0 0 S 0.0 0.0 0:00.02 events/0
7 root 5 -10 0 0 0 S 0.0 0.0 0:00.00 events/1
8 root 5 -10 0 0 0 S 0.0 0.0 0:00.09 kblockd/0
9 root 5 -10 0 0 0 S 0.0 0.0 0:00.01 kblockd/1
10 root 15 0 0 0 0 S 0.0 0.0 0:00.00 kirqd
13 root 5 -10 0 0 0 S 0.0 0.0 0:00.02 khelper/0
14 root 16 0 0 0 0 S 0.0 0.0 0:00.45 pdflush
16 root 15 0 0 0 0 S 0.0 0.0 0:00.61 kswapd0
17 root 13 -10 0 0 0 S 0.0 0.0 0:00.00 aio/0
18 root 13 -10 0 0 0 S 0.0 0.0 0:00.00 aio/1
You can further modify the processes using renice to give a new priority to each process. If a
process hangs or occupies too much CPU, you can kill the process (kill command).
process hangs or occupies too much CPU, you can kill the process (kill command).
The columns in the output are:
PID
Process identification.
USER
Name of the user who owns (and perhaps started) the process.
PRI
Priority of the process. (See 1.1.4, “Process priority and nice level” on page 5
for details.)
for details.)
netperf
Network performance benchmark
Tool
Most useful tool function