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
..
array.c	Merge branch 'for-linus' of git://selinuxproject.org/~jmorris/linux-security	2012-01-14 18:36:33 -08:00
base.c	procfs: mark thread stack correctly in proc/<pid>/maps	2012-03-21 17:54:58 -07:00
cmdline.c
consoles.c
cpuinfo.c
devices.c
generic.c	switch procfs to umode_t use	2012-01-03 22:54:56 -05:00
inode.c	switch open-coded instances of d_make_root() to new helper	2012-03-20 21:29:35 -04:00
internal.h	procfs: mark thread stack correctly in proc/<pid>/maps	2012-03-21 17:54:58 -07:00
interrupts.c
Kconfig
kcore.c	fs/proc/kcore.c: make get_sparsemem_vmemmap_info() static	2012-03-23 16:58:42 -07:00
kmsg.c
loadavg.c
Makefile
meminfo.c
mmu.c
namespaces.c	vfs: trim includes a bit	2012-01-03 22:57:13 -05:00
nommu.c
page.c	pagemap: export KPF_THP	2012-03-21 17:54:57 -07:00
proc_devtree.c
proc_net.c	switch procfs to umode_t use	2012-01-03 22:54:56 -05:00
proc_sysctl.c	security: trim security.h	2012-02-14 10:45:42 +11:00
proc_tty.c
root.c	procfs: add hidepid= and gid= mount options	2012-01-10 16:30:54 -08:00
softirqs.c
stat.c	procfs: add num_to_str() to speed up /proc/stat	2012-03-23 16:58:42 -07:00
task_mmu.c	procfs: mark thread stack correctly in proc/<pid>/maps	2012-03-21 17:54:58 -07:00
task_nommu.c	procfs: mark thread stack correctly in proc/<pid>/maps	2012-03-21 17:54:58 -07:00
uptime.c
version.c
vmcore.c	fadump: Introduce cleanup routine to invalidate /proc/vmcore.	2012-02-23 10:50:02 +11:00