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Andrei Vagin d1be35cb6f proc: add seq_put_decimal_ull_width to speed up /proc/pid/smaps
seq_put_decimal_ull_w(m, str, val, width) prints a decimal number with a
specified minimal field width.

It is equivalent of seq_printf(m, "%s%*d", str, width, val), but it
works much faster.

== test_smaps.py
  num = 0
  with open("/proc/1/smaps") as f:
          for x in xrange(10000):
                  data = f.read()
                  f.seek(0, 0)
==

== Before patch ==
  $ time python test_smaps.py
  real    0m4.593s
  user    0m0.398s
  sys     0m4.158s

== After patch ==
  $ time python test_smaps.py
  real    0m3.828s
  user    0m0.413s
  sys     0m3.408s

$ perf -g record python test_smaps.py
== Before patch ==
-   79.01%     3.36%  python   [kernel.kallsyms]    [k] show_smap.isra.33
   - 75.65% show_smap.isra.33
      + 48.85% seq_printf
      + 15.75% __walk_page_range
      + 9.70% show_map_vma.isra.23
        0.61% seq_puts

== After patch ==
-   75.51%     4.62%  python   [kernel.kallsyms]    [k] show_smap.isra.33
   - 70.88% show_smap.isra.33
      + 24.82% seq_put_decimal_ull_w
      + 19.78% __walk_page_range
      + 12.74% seq_printf
      + 11.08% show_map_vma.isra.23
      + 1.68% seq_puts

[akpm@linux-foundation.org: fix drivers/of/unittest.c build]
Link: http://lkml.kernel.org/r/20180212074931.7227-1-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
Documentation mm/page_alloc: don't reserve ZONE_HIGHMEM for ZONE_MOVABLE request 2018-04-11 10:28:32 -07:00
LICENSES LICENSES: Add MPL-1.1 license 2018-01-06 10:59:44 -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 for-4.17/block-20180402 2018-04-05 14:27:02 -07:00
certs certs/blacklist_nohashes.c: fix const confusion in certs blacklist 2018-02-21 15:35:43 -08:00
crypto MIPS changes for 4.17 2018-04-10 11:39:22 -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 kbuild: remove all dummy assignments to obj- 2017-11-18 11:46:06 +09:00
fs proc: add seq_put_decimal_ull_width to speed up /proc/pid/smaps 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 New features: 2018-04-10 11:27:30 -07:00
ipc proc: move /proc/sysvipc creation to where it belongs 2018-04-11 10:28:33 -07:00
kernel New features: 2018-04-10 11:27:30 -07:00
lib proc: add seq_put_decimal_ull_width to speed up /proc/pid/smaps 2018-04-11 10:28:33 -07:00
mm kasan, slub: fix handling of kasan_slab_free hook 2018-04-11 10:28:32 -07:00
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2018-04-09 17:04:10 -07:00
samples VFIO updates for v4.17-rc1 2018-04-06 19:44:27 -07:00
scripts Leaking-addresses patches for 4.17-rc1 2018-04-07 11:56:33 -07:00
security New features: 2018-04-10 11:27:30 -07:00
sound sound fixes for 4.17-rc1 2018-04-10 10:16:04 -07:00
tools New features: 2018-04-10 11:27:30 -07:00
usr kbuild: rename built-in.o to built-in.a 2018-03-26 02:01:19 +09:00
virt KVM/ARM updates for v4.17 2018-03-28 16:09:09 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Add hch to .get_maintainer.ignore 2015-08-21 14:30:10 -07:00
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore kbuild: move include/config/ksym/* to include/ksym/* 2018-03-26 02:01:23 +09:00
.mailmap Merge candidates for 4.17 merge window 2018-04-06 17:35:43 -07:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS MAINTAINERS/CREDITS: Drop METAG ARCHITECTURE 2018-03-05 16:34:24 +00:00
Kbuild Kbuild updates for v4.15 2017-11-17 17:45:29 -08:00
Kconfig License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
MAINTAINERS mm/hmm: documentation editorial update to HMM documentation 2018-04-11 10:28:30 -07:00
Makefile Kconfig updates for v4.17 2018-04-03 16:28:01 -07:00
README Docs: Added a pointer to the formatted docs to README 2018-03-21 09:02:53 -06:00

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.