Linux mainline fork with MSM8998 patches | https://mainline.space | Currently supported devices:
OnePlus 5/5T, Xiaomi Mi 6, F(x)tec Pro¹ (2019 QX1000 model) & Sony Xperia XZ Premium (UNTESTED!)
35da1dfd94
Avoid a long delay when a busy bit is still set and has to be polled again. Measurements on a system with 2 Opals (6097F) and one Agate (6352) show that even with this much tighter loop, we have about a 50% chance of the bit being cleared on the first poll, all other accesses see the bit being cleared on the second poll. On a standard MDIO bus running MDC at 2.5MHz, a single access with 32 bits of preamble plus 32 bits of data takes 64*(1/2.5MHz) = 25.6us. This means that mv88e6xxx_smi_direct_wait took 26us + CPU overhead in the fast scenario, but 26us + 1500us + 26us + CPU overhead in the slow case - bringing the average close to 1ms. With this change in place, the slow case is closer to 2*26us + CPU overhead, with the average well below 100us - a 10x improvement. This translates to real-world winnings. On a 3-chip 20-port system, the modprobe time drops by 88%: Before: root@coronet:~# time modprobe mv88e6xxx real 0m 15.99s user 0m 0.00s sys 0m 1.52s After: root@coronet:~# time modprobe mv88e6xxx real 0m 2.21s user 0m 0.00s sys 0m 1.54s Signed-off-by: Tobias Waldekranz <tobias@waldekranz.com> Reviewed-by: Andrew Lunn <andrew@lunn.ch> Signed-off-by: David S. Miller <davem@davemloft.net> |
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| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| 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.