From: Yuchung Cheng <ych...@google.com> Date: Wed, 16 May 2018 16:40:09 -0700
> This patch set implements the features correspond to the > draft-ietf-tcpm-rack-03 version of the RACK draft. > https://datatracker.ietf.org/meeting/101/materials/slides-101-tcpm-update-on-tcp-rack-00 > > 1. SACK: implement equivalent DUPACK threshold heuristic in RACK to > replace existing RFC6675 recovery (tcp_mark_head_lost). > > 2. Non-SACK: simplify RFC6582 NewReno implementation > > 3. RTO: apply RACK's time-based approach to avoid spuriouly > marking very recently sent packets lost. > > 4. with (1)(2)(3), make RACK the exclusive fast recovery mechanism to > mark losses based on time on S/ACK. Tail loss probe and F-RTO remain > enabled by default as complementary mechanisms to send probes in > CA_Open and CA_Loss states. The probes would solicit S/ACKs to trigger > RACK time-based loss detection. > > All Google web and internal servers have been running RACK-only mode > (4) for a while now. a/b experiments indicate RACK/TLP on average > reduces recovery latency by 10% compared to RFC6675. RFC6675 > is default-off now but can be enabled by disabling RACK (sysctl > net.ipv4.tcp_recovery=0) for unseen issues. Series applied. These patches, the design of the ordering of changes in the patch series, and the commit messages themselves were more than a pleasure to read. Really, this patch series is a great model for others who want to improve the quality and reviewability of their submissions. Thank you.
