10e361e100
Yuchung Cheng says: ==================== tcp: default RACK loss recovery 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. ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.