An overburdened CPU is another obvious place to look for performance problems
on your system. Similarly io can be a bottleneck in proper system performance. You can watch various parameters if you install sysstat package.
On Ubuntu you can install with
$ sudo apt-get install sysstat
The sysstat package contains the following system performance tools:
* sar - collects and reports system activity information;
* iostat - reports CPU utilization and I/O statistics for disks;
* mpstat - reports global and per-processor statistics;
* pidstat - reports statistics for Linux tasks (processes);
* sadf - displays data collected by sar in various formats.
See the screen shot of iostat command run from a terminal.
Iostat can display cpu usage statistics. The following command prints cpu stats every 3 sec
$ iostat -c 3
To Print time stamp with CPU report you can use
$ iostat -c -t
You can use pidstat to display detailed information on processes. See the screen shot below.