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A mirror of the official Linux kernel repository just in case
d533cb2d2a
Recent gcc versions started not systematically inline __arch_xprod64() and that has performance implications. Give the compiler the freedom to decide only when optimizing for size. Here's some timing numbers from lib/math/test_div64.c Using __always_inline: ``` test_div64: Starting 64bit/32bit division and modulo test test_div64: Completed 64bit/32bit division and modulo test, 0.048285584s elapsed ``` Without __always_inline: ``` test_div64: Starting 64bit/32bit division and modulo test test_div64: Completed 64bit/32bit division and modulo test, 0.053023584s elapsed ``` Forcing constant base through the non-constant base code path: ``` test_div64: Starting 64bit/32bit division and modulo test test_div64: Completed 64bit/32bit division and modulo test, 0.103263776s elapsed ``` It is worth noting that test_div64 does half the test with non constant divisors already so the impact is greater than what those numbers show. And for what it is worth, those numbers were obtained using QEMU. The gcc version is 14.1.0. Signed-off-by: Nicolas Pitre <npitre@baylibre.com> Signed-off-by: Arnd Bergmann <arnd@arndb.de> |
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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.