Description
Goal: The goal of this lab is to get familiar with Linux tools and files used for system and
process behaviour information and monitoring.
Important instructions:
1. Login as labuser for this assignment on the SL2 machines
2. This file is part the lab1.tar.gz archive which contains multiple directories with programs
associated with exercise questions to follow.
Tools: Following are some basic Linux tools. The first step of this lab is to get familiar with the
usage and capabilities of these tools.
To know more about them use: man . Start with man man!
● top
The top program provides a dynamic real-time view of a running system. It can display
system summary information, as well as a list of processes or threads currently being
managed by the kernel. The types of system summary information shown and the types,
order and size of information displayed for tasks are all user-configurable.
● ps
The ps command is used to view the processes running on a system. It provides a
snapshot of the current processes along with detailed information like user id, cpu
usage, memory usage, command name etc. It does not display data in real time like top
or htop commands, but even though being simpler in features and output it is still an
essential process management/monitoring tool that every linux newbie should know
about and learn well.
● iostat
iostat is a command used for monitoring input/output device usage by observing the
time the devices are active in relation to their average transfer rates. iostat creates
reports that can be used to change system configuration for better balance the
input/output between physical disks.
● strace
strace is a diagnostic, debugging and instructional userspace utility for Linux. It is used
to monitor interactions between processes and the Linux kernel, which include system
calls, signal deliveries, and changes of process state.
● lsof
lsof is a tool used to list open files based on user, process, commands, network
services, etc.
● lsblk
lsblk is a tool used to list information about all available block devices such as hard
disk, flash drives, CD-ROM…
● Also look up the following commands: pstree, lshw, lspci, lscpu, dig,
netstat, df, du. (note that some of these may need root privileges)
The /proc file system
The /proc file system is a mechanism provided by Linux, so that kernel can send
information to processes and also report information about the system and processes to users.
This is a file interface provided to the user, to interact with the kernel and get the required
information about processes running on the system. The /proc file system is nicely
documented in the proc man page. You can access this document by running the command
man proc on a Linux system. Understand systemwide proc files such as meminfo, cpuinfo,
etc and process related files such as status, stat, limits, maps etc.
Exercises
1. Collect the following basic information about your machine using the /proc file system
and answer the following questions:
a. How many CPU and cores does the machine have?
b. What is the frequency of each CPU ?
c. How much memory does your system have?
d. How much of it is free and available? What is the difference between them?
e. What is total number of user-level processes in the system?
f. How many context switches has the system performed since bootup?
2. Run all programs in the subdirectory memory and identify memory usage of each
program. What is the meaning of the parameters VmSize and VmRSS?
Compare the memory usage of these programs in terms of VmSize & VmRSS and justify
your results based on code.
3. Run the executable subprocesses provided in the subdirectory subprocess and
provide your roll number as input argument. Find the number of sub processes created
by this program. Describe how you obtained the answer.
4. Run strace along with the binary program of empty.c given in subdirectory strace.
What do you think the output of strace indicates in this case? How many different system
call functions do you see?
Next, use strace along with another binary program of hello.c (which is in the same
directory).
Compare the two strace outputs
a. Which part of the strace output is common, and which part has to do with the
specific program?
b. List all unique system calls along with input and output parameters and overall
functionality of each system call ?
5. Run the executable openfiles in subdirectory files and list the files which are
opened by this program. Describe how you obtained the answer.
6. Find all the block devices on your system, their mount points and file systems present on
them. Describe how you obtained the answer.
7. Create 5000 files starting from foo1.pdf to foo5000.pdf using script.sh given
in the subdirectory disk.
Run the programs disk1 and disk2 and identify the average disk utilization. Justify
your answer with the help of code.
Submission details
● All submissions via moodle. Name your submissions as:
● The tar should contain the following …
○ lab1.pdf which states the answer for each question and provides a justification for
the same based on outputs of tools used. Make sure to provide snapshots or
other details from tools used to justify.
○ In addition, for each question place relevant in the corresponding subdirectories.
Filenames should relate to question number.
For example: output-1a.txt for output of question 1a. Use further suffixes in case
of multiple outputs.
● Deadline: 22nd July 11.59 A.M.
Expected time for completion of lab: 2-3 hours
