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Vladimir Oltean a3d91b2c6f net/sched: taprio: warn about missing size table
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>
2023-02-08 09:48:53 +00:00
arch Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2023-02-02 14:49:55 -08:00
block block-6.2-2023-01-20 2023-01-20 12:44:41 -08:00
certs certs: make system keyring depend on built-in x509 parser 2022-09-24 04:31:18 +09:00
crypto wifi: cfg80211: Deduplicate certificate loading 2023-01-19 14:46:45 +01:00
Documentation dt-bindings: net: micrel-ksz90x1.txt: Update for lan8841 2023-02-08 09:16:07 +00:00
drivers net/sched: taprio: give higher priority to higher TCs in software dequeue mode 2023-02-08 09:48:52 +00:00
fs Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2023-02-02 14:49:55 -08:00
include net/sched: taprio: give higher priority to higher TCs in software dequeue mode 2023-02-08 09:48:52 +00:00
init bpf-next-for-netdev 2023-01-28 00:00:14 -08:00
io_uring io_uring: always prep_async for drain requests 2023-01-27 06:29:29 -07:00
ipc Non-MM patches for 6.2-rc1. 2022-12-12 17:28:58 -08:00
kernel sched/topology: Introduce sched_numa_hop_mask() 2023-02-07 18:20:00 -08:00
lib lib/cpumask: update comment for cpumask_local_spread() 2023-02-07 18:20:00 -08:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm Revert "mm/compaction: fix set skip in fast_find_migrateblock" 2023-01-29 10:38:43 -08:00
net net/sched: taprio: warn about missing size table 2023-02-08 09:48:53 +00:00
rust rust: print: avoid evaluating arguments in pr_* macros in unsafe blocks 2023-01-16 00:54:35 +01:00
samples Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2023-02-02 14:49:55 -08:00
scripts Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2023-02-02 14:49:55 -08:00
security tomoyo: Update website link 2023-01-13 23:11:38 +09:00
sound sound fixes for 6.2-rc7 2023-02-01 10:26:23 -08:00
tools selftests: forwarding: bridge_mdb_max: Add a new selftest 2023-02-06 08:48:27 +00:00
usr usr/gen_init_cpio.c: remove unnecessary -1 values from int file 2022-10-03 14:21:44 -07:00
virt VFIO fixes for v6.2-rc6 2023-01-23 11:56:07 -08:00
.clang-format iommufd for 6.2 2022-12-14 09:15:43 -08:00
.cocciconfig
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: ignore *.rpm 2022-12-30 17:22:14 +09:00
.mailmap mailmap: add John Crispin's entry 2023-02-02 11:35:33 -08:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: update SCTP maintainers 2023-02-02 11:35:33 -08:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS dt-bindings: net: Add Motorcomm yt8xxx ethernet phy 2023-02-03 09:34:50 +00:00
Makefile Linux 6.2-rc6 2023-01-29 13:59:43 -08:00
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.