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| - | ==== 03. [5p] Iotop ==== | ||
| - | === Good to know === | ||
| - | |||
| - | **Iotop** is an utility similar to top command, that interfaces with the kernel to provide per-thread/process I/O usage statistics. | ||
| - | |||
| - | <code> | ||
| - | Debian/Ubuntu Linux install iotop | ||
| - | $ sudo apt-get install iotop | ||
| - | |||
| - | How to use iotop command | ||
| - | $ sudo iotop OR $ iotop | ||
| - | </code> | ||
| - | |||
| - | Supported options by iotop command: | ||
| - | |||
| - | | **Options** | **Description** ^^ | ||
| - | | --version | show program’s version number and exit || | ||
| - | | -h, --help | show this help message and exit || | ||
| - | | -o, --only | only show processes or threads actually doing I/O || | ||
| - | | -b, --batch | non-interactive mode || | ||
| - | | -n NUM, --iter=NUM | number of iterations before ending [infinite] || | ||
| - | | -d SEC, --delay=SEC | delay between iterations [1 second] || | ||
| - | | -p PID, --pid=PID | processes/threads to monitor [all] || | ||
| - | | -u USER, --user=USER | users to monitor [all] || | ||
| - | | -P, --processes | only show processes, not all threads || | ||
| - | | -a, --accumulated | show accumulated I/O instead of bandwidth || | ||
| - | | -k, --kilobytes | use kilobytes instead of a human friendly unit || | ||
| - | | -t, --time | add a timestamp on each line (implies –batch) || | ||
| - | | -q, --quiet | suppress some lines of header (implies –batch) || | ||
| - | |||
| - | === Monitoring the behaviour === | ||
| - | |||
| - | Datafile: {{:ep:laboratoare:dummy.sh|dummy.sh}}. | ||
| - | |||
| - | * Run iotop (install it if you do not already have it) in a separate shell showing only processes or threads actually doing I/O. | ||
| - | * Inspect the script code (**dummy.sh**) to see what it does. | ||
| - | * Monitor the behaviour of the system with iotop while running the script. | ||
| - | * Identify the PID and PPID of the process running the dummy script and kill the process using command line from another shell (sending SIGINT signal to both parent & child processes). | ||
| - | * Hint - [[https://superuser.com/questions/150117/how-to-get-parent-pid-of-a-given-process-in-gnu-linux-from-command-line|How to get parent PID of a given process in GNU/Linux from command line?]] | ||
| - | |||
| - | <solution -hidden> | ||
| - | {{:ep:laboratoare:lab3-ex4.png?600}} | ||
| - | |||
| - | Find PPID from PID: ps -o ppid= -p PID | ||
| - | |||
| - | Send SIGINT signal: kill -SIGINT PID,PPID | ||
| - | </solution> | ||
