64109f1dc4
Changed "priv.clock.lock" lock from 'rw_lock' to 'seq_lock' in order to improve packet rate performance. Tested on Intel(R) Xeon(R) CPU E5-2660 v2 @ 2.20GHz. Sent 64b packets between two peers connected by ConnectX-5, and measured packet rate for the receiver in three modes: no time-stamping (base rate) time-stamping using rw_lock (old lock) for critical region time-stamping using seq_lock (new lock) for critical region Only the receiver time stamped its packets. The measured packet rate improvements are: Single flow (multiple TX rings to single RX ring): without timestamping: 4.26 (M packets)/sec with rw-lock (old lock): 4.1 (M packets)/sec with seq-lock (new lock): 4.16 (M packets)/sec 1.46% improvement Multiple flows (multiple TX rings to six RX rings): without timestamping: 22 (M packets)/sec with rw-lock (old lock): 11.7 (M packets)/sec with seq-lock (new lock): 21.3 (M packets)/sec 82.05% improvement The packet rate improvement is due to the lack of atomic operations for the 'readers' by the seq-lock. Since there are much more 'readers' than 'writers' contention on this lock, almost all atomic operations are saved. this results in a dramatic decrease in overall cache misses. Signed-off-by: Shay Agroskin <shayag@mellanox.com> Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
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.