12ff91c8ba
Yuchung Cheng says: ==================== improving TCP behavior on host congestion This patch set aims to improve how TCP handle local qdisc congestion by simplifying the previous implementation. Previously when an skb fails to (re)transmit due to local qdisc congestion or other resource issue, TCP refrains from setting the skb timestamp or the recovery starting time. This design makes determining when to abort a stalling socket more complicated, as the timestamps of these tranmission attempts were missing. The stack needs to sort of infer when the original attempt happens. A by-product is a socket may disregard the system timeout limit (i.e. sysctl net.ipv4.tcp_retries2 or USER_TIMEOUT option), and continue to retry until the transmission is successful. In data-center environment when TCP RTO is small, this could cause the socket to retry frequently for long during qdisc congestion. The solution is to first unconditionally timestamp skb and recovery attempt. Then retry more conservatively (twice a second) on local qdisc congestion but abort the sockets according to the system limit. ==================== Signed-off-by: David S. Miller <davem@davemloft.net> |
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| README | ||
README
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.
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.