warothia

For my master’s thesis, I looked at how to get better throughput over 5G mmWave, which has really unpredictable bandwidth. Just using a big BFIFO buffer (sized to the BDP) gave us twice the throughput of FQ-CoDel, but at the cost of high jitter and bad latency for interactive traffic. To fix that, I wrote a non-transparent Performance Enhancing Proxy (PEP) as a Linux kernel module in C. It mixes big buffers with FQ-CoDel and manages to get both high, stable throughput and low latency impact.

It would be really interesting if it was possible to use other languages which can be compiled to .so files. Will look into it!

Initially I did use fork a lot to allow each handler in its own “process” mainly because I wanted to isolate it as well in a container fashion. However the overhead became to much at the start when I just wanted it to work. Will be looking into it again!

You’re absolutely right, I have not tried very hard to optimize for speed either yet. To comment was more directed at the fact most just say that “speed” is the main reason to use C, but for me it’s almost exclusively for the fun and “cool” factor.

Thanks! Yes, an arena allocator for each request is on my todo list. Just didn’t get to implementing it yet. :D

Oh! Did not know that, interesting. I guess they are more alike then.

Few others have brought up Apache Modules, and they are incredibly similar to my idea. :D Did not know about them while I was developing it. The main difference as far as I could see was the fact that you had to recompile / restart the server. Which I try to avoid, so little changes require almost no recompiling.

If you would want to link with external libraries, you would need to modify to server and make sure it has access to them when compiling the modules.

Oh really interesting, will look into it! Was afraid it would leak memory.

I could say speed, but the main reason for me is because it is fun. And I like to see what I can make C do. :D

This hobby project is inspired by kernel modules and AWS Lambda. It lets you write raw C modules, upload them, and have the server compile and run only the module itself at runtime—no need to recompile the entire application or restart the server.

You can update routes and modules dynamically. Even WebSocket handlers can be updated without dropping existing connections.