[Bloat] Trying to *really* understand Linux pacing

[Michael Welzl]

Dear de-bloaters of buffers,
Esteemed experts of low delay and pacing!

I have no longer been satisfied with high-level descriptions of how pacing works in Linux, and how it interacts with TSQ (I’ve seen some, in various papers, over the years) - but I wanted to REALLY understand it. So, I have dug through the code.

I documented this experience here:
https://docs.google.com/document/d/1-uXnPDcVBKmg5krkG5wYBgaA2yLSFK_kZa7xGDWc7XU/edit?usp=sharing <https://docs.google.com/document/d/1-uXnPDcVBKmg5krkG5wYBgaA2yLSFK_kZa7xGDWc7XU/edit?usp=sharing>
but it has some holes and may have mistakes.

Actually, my main problem is that I don’t really know what goes on when I configure a larger IW… things seem to get quite “off” there. Why? Anyone up for solving that riddle?  ;-)
(see the tests I documented towards the end of the document)

Generally, if someone who has their hands on files such as tcp_output.c all the time could take a look, and perhaps “fill” my holes, or improve anything that might be wrong, that would be fantastic!   I think that anyone should be allowed to comment and make suggestions in this doc.

MANY thanks to whoever finds the time to take a look !

Cheers,
Michael

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.bufferbloat.net/pipermail/bloat/attachments/20240207/5fe0a72f/attachment.html>