The module is the final result of Advanced Operating Systems course held in the Master's Degree in Computer Science & Engineering at Politecnico di Milano, Italy.
- Project supervisor: Vittorio Zaccaria
- Course head professor: Vittorio Zaccaria
- Student developer: Francesco Aristei
Specifically, it consists in developing the FSM server implemented in the aos_playground repository, using the io_uring inteface.
The performances of the server are then evaluated against the other concurrency models already provided.
The fsm implemented by the server is a simple one. One state machine is dynamically created for each client. Each client can send an action represented by a char (0 .. 3) to change a client-specific state (a ... d) in the server. This structure allows to model several interactions. Any web application parses actions from the client to change its own state.
io_uring is a Linux kernel interface that efficiently allow to send and receive data asynchronously.
It was originally designed to target block devices and files but has since gained the ability to work with things like network sockets, like in our case.
In the Report folder, there is the official and complete documentation of the project. The .tex file is the LaTeX documentation, which can be compiled on a local machine. The pdf file is the already compiled LaTeX document. There is a thorough high-level description of the code.
Even though the purpose of the project is to implement the server only using the io_uring interface, all the servers already present in the aos_playground repository, have been used in this repository, in order to implement the performance benchmarking.
To play with the servers implemented, first is necessary to open a terminal.
From here, starting from the root directory of the project, is required to move inside the src/servers dir.
Here are located the files containing the code of the different servers.
Now, to run a specific implementation of the finite state machine, execute the following instructions contained in the makefile.
make utils.oto generate the object file from the utils.cmake state.oto generate the object file from the state.cmake <name_of_the _server>to obtain the executable of the server
After that, the server is run with the command ./<name_of_executable>.
Now, it will be listening on the localhost, on port 9090.
To interact with it, open a second terminal and connect to the fsm using for example the telnet protocol, with the following command:
telnet localhost 9090
From now on, this terminal can be used to send messages to the server and read in the stdout the corresponding state of the machine changing, accordingly to the action requested.
Finally, execute the make clean command to remove the files created above.
Part of the project is to evaluate the goodness of one concurrency model against the other.
In order to do so, a simple benchmark application has been written.
Starting from the root directory of the project, open a terminal, and produce the executable from the benchmark.c with the following command:
gcc benchmark.c -o benchmark
Then, run the server you want to evaluate, using the steps described in the simple usage paragraph. Finally, test the server, executing the benchmark with the following:
./benchmark <number_of_clients> <duration_of_the_interaction_in_seconds>
The results of the testing are written in the stdout.
In the no_benchmark folder, the two models are implemented in order to be fully compatible with the AOS-playground code.
The models doesn't send back any ack to the client after having received and processed the new action to perform on the fsm.
The module has been developed in Ubuntu 22.04 LTS distro with development tools on a Virtual Machine.
Kernel version: v5.15.
- Efficient IO with io_uring - The main reference article explaining the io_uring interface.
- Lord of the io_uring - A very useful blog describing the io_uring technology with lots of tutorial and practical examples. A very detailed explanation of the liburing API is also provided.