opportunistically reduce the number of ack ranges added to sentmap #487
Conversation
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
janaiyengar
approved these changes
Sep 1, 2021
Collaborator
janaiyengar
left a comment
janaiyengar
left a comment
There was a problem hiding this comment.
Nice optimization! Looks good to me; thanks @kazuho!
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
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Outdated suggestions cannot be applied.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.
At the moment, each ACK range takes up to 64
quicly_sent_tslots, where 64 is the maximum number of ACK ranges that quicly retains.These become a pressure when the peer reaches the end of its slow start, because:
This PR mitigates the pressure by opportunistically storing at most 8 ranges within one
quicly_sent_t.This PR should at least mitigate #364, by reducing the number of entries in the sentmap to 1/8. If that's not enough, we can reduce the numbers of entries further by 1/4, by adopting #488. Anyways, the first step would be to adopt this PR, as it fixes the memory footprint issue as well (see the 2nd point above).