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The launchtime offset should be corrected according to sections 7.5.2.6 Transmit Scheduling Latency of the Intel Ethernet I225/I226 Software User Manual. Software can compensate the latency between the transmission scheduling and the time that packet is transmitted to the network by setting this GTxOffset register. Without setting this register, there may be a significant delay between the packet scheduling and the network point. This patch helps to reduce the latency for each of the link speed. Before: 10Mbps : 11000 - 13800 nanosecond 100Mbps : 1300 - 1700 nanosecond 1000Mbps : 190 - 600 nanosecond 2500Mbps : 1400 - 1700 nanosecond After: 10Mbps : less than 750 nanosecond 100Mbps : less than 192 nanosecond 1000Mbps : less than 128 nanosecond 2500Mbps : less than 128 nanosecond Test Setup: Talker : Use l2_tai.c to generate the launchtime into packet payload. Listener: Use timedump.c to compute the delta between packet arrival and LaunchTime packet payload. Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@intel.com> Signed-off-by: Muhammad Husaini Zulkifli <muhammad.husaini.zulkifli@intel.com> Acked-by: Sasha Neftin <sasha.neftin@intel.com> Acked-by: Paul Menzel <pmenzel@molgen.mpg.de> Tested-by: Naama Meir <naamax.meir@linux.intel.com> Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.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.
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.