KAMEZAWA Hiroyuki 1ac101a5d6 procfs: add num_to_str() to speed up /proc/stat ... == stat_check.py num = 0 with open("/proc/stat") as f: while num < 1000 : data = f.read() f.seek(0, 0) num = num + 1 == perf shows 20.39% stat_check.py [kernel.kallsyms] [k] format_decode 13.41% stat_check.py [kernel.kallsyms] [k] number 12.61% stat_check.py [kernel.kallsyms] [k] vsnprintf 10.85% stat_check.py [kernel.kallsyms] [k] memcpy 4.85% stat_check.py [kernel.kallsyms] [k] radix_tree_lookup 4.43% stat_check.py [kernel.kallsyms] [k] seq_printf This patch removes most of calls to vsnprintf() by adding num_to_str() and seq_print_decimal_ull(), which prints decimal numbers without rich functions provided by printf(). On my 8cpu box. == Before patch == [root@bluextal test]# time ./stat_check.py real 0m0.150s user 0m0.026s sys 0m0.121s == After patch == [root@bluextal test]# time ./stat_check.py real 0m0.055s user 0m0.022s sys 0m0.030s [akpm@linux-foundation.org: remove incorrect comment, use less statck in num_to_str(), move comment from .h to .c, simplify seq_put_decimal_ull()] [andrea@betterlinux.com: avoid breaking the ABI in /proc/stat] Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrea Righi <andrea@betterlinux.com> Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: Glauber Costa <glommer@parallels.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Ingo Molnar <mingo@elte.hu> Cc: Paul Turner <pjt@google.com> Cc: Russell King <rmk@arm.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		2012-03-23 16:58:42 -07:00
..
acpi
asm-generic	coredump: add VM_NODUMP, MADV_NODUMP, MADV_CLEAR_NODUMP	2012-03-23 16:58:42 -07:00
crypto	crypto: remove the second argument of k[un]map_atomic()	2012-03-20 21:48:16 +08:00
drm	headers: include linux/types.h where appropriate	2012-03-23 16:58:31 -07:00
keys
linux	procfs: add num_to_str() to speed up /proc/stat	2012-03-23 16:58:42 -07:00
math-emu
media
misc
mtd
net	poll: add poll_requested_events() and poll_does_not_wait() functions	2012-03-23 16:58:38 -07:00
pcmcia
rdma	Merge branches 'cma', 'cxgb3', 'cxgb4', 'ehca', 'iser', 'mad', 'nes', 'qib', 'srp' and 'srpt' into for-next	2012-03-19 09:50:33 -07:00
rxrpc
scsi	headers: include linux/types.h where appropriate	2012-03-23 16:58:31 -07:00
sound	headers: include linux/types.h where appropriate	2012-03-23 16:58:31 -07:00
target	target: Use array_zalloc for device_list	2012-03-15 19:15:51 -07:00
trace	NFS client updates for Linux 3.4	2012-03-23 08:53:47 -07:00
video	fbdev: sh_mipi_dsi: add extra phyctrl for sh_mipi_dsi_info	2012-03-21 07:24:01 +00:00
xen	include/ and checkpatch: prefer __scanf to __attribute__((format(scanf,...)	2012-03-23 16:58:36 -07:00
Kbuild