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a3d91b2c6f
Vinicius intended taprio to take the L1 overhead into account when estimating packet transmission time through user input, specifically through the qdisc size table (man tc-stab). Something like this: tc qdisc replace dev $eth root stab overhead 24 taprio \ num_tc 8 \ map 0 1 2 3 4 5 6 7 \ queues 1@0 1@1 1@2 1@3 1@4 1@5 1@6 1@7 \ base-time 0 \ sched-entry S 0x7e 9000000 \ sched-entry S 0x82 1000000 \ max-sdu 0 0 0 0 0 0 0 200 \ flags 0x0 clockid CLOCK_TAI Without the overhead being specified, transmission times will be underestimated and will cause late transmissions. For an offloading driver, it might even cause TX hangs if there is no open gate large enough to send the maximum sized packets for that TC (including L1 overhead). Properly knowing the L1 overhead will ensure that we are able to auto-calculate the queueMaxSDU per traffic class just right, and avoid these hangs due to head-of-line blocking. We can't make the stab mandatory due to existing setups, but we can warn the user that it's important with a warning netlink extack. Link: https://patchwork.kernel.org/project/netdevbpf/patch/20220505160357.298794-1-vladimir.oltean@nxp.com/ Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com> Reviewed-by: Kurt Kanzenbach <kurt@linutronix.de> 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.
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.