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Filename Latest commit message Latest commit date
Andrei Vagin 48dffbf82d proc: optimize single-symbol delimiters to spead up seq_put_decimal_ull
A delimiter is a string which is printed before a number.  A
syngle-symbol delimiters can be printed by set_putc() and this works
faster than printing by set_puts().

== test_proc.c

int main(int argc, char **argv)
{
	int n, i, fd;
	char buf[16384];

	n = atoi(argv[1]);
	for (i = 0; i < n; i++) {
		fd = open(argv[2], O_RDONLY);
		if (fd < 0)
			return 1;
		if (read(fd, buf, sizeof(buf)) <= 0)
			return 1;
		close(fd);
	}

	return 0;
}
==

$ time ./test_proc  1000000 /proc/1/stat

== Before patch ==
  real	0m3.820s
  user	0m0.337s
  sys	0m3.394s

== After patch ==
  real	0m3.110s
  user	0m0.324s
  sys	0m2.700s

Link: http://lkml.kernel.org/r/20180212074931.7227-3-avagin@openvz.org
Signed-off-by: Andrei Vagin <avagin@openvz.org>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-04-11 10:28:33 -07:00
arch ARM: CMA: avoid double mapping to the CMA area if CONFIG_HIGHMEM=y 2018-04-11 10:28:32 -07:00
block
certs
crypto
Documentation mm/page_alloc: don't reserve ZONE_HIGHMEM for ZONE_MOVABLE request 2018-04-11 10:28:32 -07:00
drivers proc: add seq_put_decimal_ull_width to speed up /proc/pid/smaps 2018-04-11 10:28:33 -07:00
firmware
fs proc: optimize single-symbol delimiters to spead up seq_put_decimal_ull 2018-04-11 10:28:33 -07:00
include proc: add seq_put_decimal_ull_width to speed up /proc/pid/smaps 2018-04-11 10:28:33 -07:00
init
ipc proc: move /proc/sysvipc creation to where it belongs 2018-04-11 10:28:33 -07:00
kernel
lib proc: add seq_put_decimal_ull_width to speed up /proc/pid/smaps 2018-04-11 10:28:33 -07:00
LICENSES
mm kasan, slub: fix handling of kasan_slab_free hook 2018-04-11 10:28:32 -07:00
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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.
See Documentation/00-INDEX for a list of what is contained in each file.

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.