Colin Ian King 9fa26fb554 mm/mincore: improve performance by adding an unlikely hint
Adding an unlikely() hint on the masked start comparison error return path
improves run-time performance of the mincore system call.

Benchmarking on an i9-12900 shows an improvement of 7ns on mincore calls
on a 256KB mmap'd region where 50% of the pages we resident.  Improvement
was from ~970 ns down to 963 ns, so a small ~0.7% improvement.

Results based on running 20 tests with turbo disabled (to reduce clock
freq turbo changes), with 10 second run per test and comparing the number
of mincores calls per second.  The % standard deviation of the 20 tests
was ~0.10%, so results are reliable.

Link: https://lkml.kernel.org/r/20250219083607.5183-1-colin.i.king@gmail.com
Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Cc: Matthew Wilcow <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-03-16 22:06:32 -07:00
2024-09-01 20:43:24 -07:00
2025-03-16 22:06:23 -07:00
2025-02-04 11:27:45 -05:00
2022-09-28 09:02:20 +02:00
2025-03-16 22:06:01 -07:00
2025-03-09 13:45:25 -10:00
2024-03-18 03:36:32 -06:00

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.
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