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Offloading drivers may report some additional statistics counters, some of them even suggested by 802.1Q, like TransmissionOverrun. In my opinion we don't have to limit ourselves to reporting counters only globally to the Qdisc/interface, especially if the device has more detailed reporting (per traffic class), since the more detailed info is valuable for debugging and can help identifying who is exceeding its time slot. But on the other hand, some devices may not be able to report both per TC and global stats. So we end up reporting both ways, and use the good old ethtool_put_stat() strategy to determine which statistics are supported by this NIC. Statistics which aren't set are simply not reported to netlink. For this reason, we need something dynamic (a nlattr nest) to be reported through TCA_STATS_APP, and not something daft like the fixed-size and inextensible struct tc_codel_xstats. A good model for xstats which are a nlattr nest rather than a fixed struct seems to be cake. # Global stats $ tc -s qdisc show dev eth0 root # Per-tc stats $ tc -s class show dev eth0 Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com> Acked-by: Vinicius Costa Gomes <vinicius.gomes@intel.com> 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.