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Klaus Kudielka says:
====================
net: dsa: mv88e6xxx: accelerate C45 scan
Starting with commit 1a136ca2e0 ("net: mdio: scan bus based on bus
capabilities for C22 and C45"), mdiobus_scan_bus_c45() is being called on
buses with MDIOBUS_NO_CAP. On a Turris Omnia (Armada 385, 88E6176 switch),
this causes a significant increase of boot time, from 1.6 seconds, to 6.3
seconds. The boot time stated here is until start of /init.
Further testing revealed that the C45 scan is indeed expensive (around
2.7 seconds, due to a huge number of bus transactions), and called twice.
Two things were suggested:
(1) to move the expensive call of mv88e6xxx_mdios_register() from
mv88e6xxx_probe() to mv88e6xxx_setup().
(2) to mask apparently non-existing phys during probing.
Before that:
Patch #1 prepares the driver to handle the movement of
mv88e6xxx_mdios_register() to mv88e6xxx_setup() for cross-chip DSA trees.
Patch #2 is preparatory code movement, without functional change.
With those changes, boot time on the Turris Omnia is back to normal.
Link: https://lore.kernel.org/lkml/449bde236c08d5ab5e54abd73b645d8b29955894.camel@gmail.com/
====================
Link: https://lore.kernel.org/r/20230315163846.3114-1-klaus.kudielka@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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
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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.