feat: Use fq packet scheduler when BBR is enabled#338
Merged
Conversation
BBR relies on pacing that is currently only implemented on fq[1]. While this is not mandatory since [2], research[3][4][5][6] has shown that fq is still preferable to use, not only on BBR but also as a general packet scheduler on host systems. With that in mind, we can adopt using fq as the default globally in our config instead, but since this requires further consideration, let's just set this when BBR is enabled for now. This is not set on the server kernel where using fq_codel seems to be more desirable. [1] https://man7.org/linux/man-pages/man8/tc-fq.8.html [2] https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git/commit/?id=218af599fa635b107cfe10acf3249c4dfe5e4123 [3] https://research.cec.sc.edu/files/cyberinfra/files/BBR%20-%20Fundamentals%20and%20Updates%202023-08-29.pdf [4] https://groups.google.com/g/bbr-dev/c/4jL4ropdOV8/m/zNQa-cv7AAAJ - See points 3 and last 2 sentences [5] https://groups.google.com/g/bbr-dev/c/4jL4ropdOV8/m/0-bNH-KEBgAJ [6] https://github.com/torvalds/linux/blob/master/net/ipv4/tcp_bbr.c#L55-L57 Signed-off-by: Eric Naim <dnaim@cachyos.org>
ptr1337
approved these changes
Nov 27, 2024
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
4 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
BBR relies on pacing that is currently only implemented on fq[1]. While this is not mandatory since [2], research[3][4][5][6] has shown that fq is still preferable to use, not only on BBR but also as a general packet scheduler on host systems. With that in mind, we can adopt using fq as the default globally in our config instead, but since this requires further consideration, let's just set this when BBR is enabled for now.
This is not set on the server kernel where using fq_codel seems to be more desirable.
[1] https://man7.org/linux/man-pages/man8/tc-fq.8.html
[2] https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git/commit/?id=218af599fa635b107cfe10acf3249c4dfe5e4123
[3] https://research.cec.sc.edu/files/cyberinfra/files/BBR%20-%20Fundamentals%20and%20Updates%202023-08-29.pdf
[4] https://groups.google.com/g/bbr-dev/c/4jL4ropdOV8/m/zNQa-cv7AAAJ - See points 3 and last 2 sentences
[5] https://groups.google.com/g/bbr-dev/c/4jL4ropdOV8/m/0-bNH-KEBgAJ
[6] https://github.com/torvalds/linux/blob/master/net/ipv4/tcp_bbr.c#L55-L57