Differential D42918

tcp: shift PRR sending cadence left to prevent long runs of ACKs not clocking out a segment
ClosedPublic
Actions

Authored by rscheff on Dec 5 2023, 10:47 PM.

Tags

None

Referenced Files

	Unknown Object (File)
	Wed, Dec 31, 1:22 AM

	Unknown Object (File)
	Wed, Dec 24, 1:50 PM

	Unknown Object (File)
	Wed, Dec 24, 1:12 PM

	Unknown Object (File)
	Dec 7 2025, 6:10 AM

	Unknown Object (File)
	Nov 30 2025, 9:59 PM

	Unknown Object (File)
	Nov 26 2025, 6:29 PM

	Unknown Object (File)
	Nov 8 2025, 3:21 PM

	Unknown Object (File)
	Nov 2 2025, 11:09 AM

View All 82 Files

Subscribers

Details

Reviewers

cc
thj
rrs
jtl
glebius
zlei
tuexen

Group Reviewers

Commits

rG35707083c6fb: tcp: shift PRR sending cadence slightly left
rG9276ad23b872: tcp: shift PRR sending cadence slightly left

Summary

PRR currently can start by waiting a short run of ACKs
without sending any segments - partially due to limited
transmit.

This change pulls the transmission opportunities slightly
leftward, preventing long runs of ACKs (initially up to 4)
before a segment is allowed for transmit. Depending on
the expected cwnd reduction, and if ACK compression is
happening, at most every other ACK should now elicit a
new segment.

Diff Detail

Repository

rG FreeBSD src repository

Lint

Lint Not Applicable

Unit

Tests Not Applicable

Event Timeline

rscheff created this revision.Dec 5 2023, 10:47 PM

Herald added a reviewer: transport. · View Herald TranscriptDec 5 2023, 10:47 PM

Herald added subscribers: melifaro, imp. · View Herald Transcript

rscheff requested review of this revision.Dec 5 2023, 10:47 PM

Harbormaster completed remote builds in B54808: Diff 131055.Dec 5 2023, 10:48 PM

tuexen accepted this revision.Dec 7 2023, 12:29 PM

This revision is now accepted and ready to land.Dec 7 2023, 12:29 PM

Closed by commit rG9276ad23b872: tcp: shift PRR sending cadence slightly left (authored by rscheff). · Explain WhyDec 7 2023, 2:40 PM

This revision was automatically updated to reflect the committed changes.

rscheff added a commit: rG9276ad23b872: tcp: shift PRR sending cadence slightly left.

rscheff added a commit: rG35707083c6fb: tcp: shift PRR sending cadence slightly left.Dec 14 2023, 11:06 AM

Revision Contents
Changeset List

Path

Size

sys/

netinet/

2 lines

Diff 131133

sys/netinet/tcp_input.c

Loading...