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Asbjørn Sloth Tønnesen says: ==================== make skip_sw actually skip software During development of flower-route[1], which I recently presented at FOSDEM[2], I noticed that CPU usage, would increase the more rules I installed into the hardware for IP forwarding offloading. Since we use TC flower offload for the hottest prefixes, and leave the long tail to the normal (non-TC) Linux network stack for slow-path IP forwarding. We therefore need both the hardware and software datapath to perform well. I found that skip_sw rules, are quite expensive in the kernel datapath, since they must be evaluated and matched upon, before the kernel checks the skip_sw flag. This patchset optimizes the case where all rules are skip_sw, by implementing a TC bypass for these cases, where TC is only used as a control plane for the hardware path. v4: - Rebased onto net-next, now that net-next is open again v3: https://lore.kernel.org/netdev/20240306165813.656931-1-ast@fiberby.net/ - Patch 3: - Fix source_inline - Fix build failure, when CONFIG_NET_CLS without CONFIG_NET_CLS_ACT. v2: https://lore.kernel.org/netdev/20240305144404.569632-1-ast@fiberby.net/ - Patch 1: - Add Reviewed-By from Jiri Pirko - Patch 2: - Move code, to avoid forward declaration (Jiri). - Patch 3 - Refactor to use a static key. - Add performance data for trapping, or sending a packet to a non-existent chain (as suggested by Marcelo). v1: https://lore.kernel.org/netdev/20240215160458.1727237-1-ast@fiberby.net/ [1] flower-route https://github.com/fiberby-dk/flower-route [2] FOSDEM talk https://fosdem.org/2024/schedule/event/fosdem-2024-3337-flying-higher-hardware-offloading-with-bird/ ==================== 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 reStructuredText 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.