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| author | Andrei Vagin <avagin@openvz.org> | 2018-04-11 02:31:16 +0300 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2018-04-11 20:28:33 +0300 |
| commit | d1be35cb6f96975d792a1535d3fe9b75239065ee (patch) | |
| tree | 42041a8e13b193af75214bd5286edb8ec0bdc167 /drivers/of/unittest.c | |
| parent | 2acddbe8168967adebf4623923242c9a4f9e1aee (diff) | |
| download | linux-d1be35cb6f96975d792a1535d3fe9b75239065ee.tar.xz | |
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>
Diffstat (limited to 'drivers/of/unittest.c')
| -rw-r--r-- | drivers/of/unittest.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/of/unittest.c b/drivers/of/unittest.c index 02c5984ab09b..6bb37c18292a 100644 --- a/drivers/of/unittest.c +++ b/drivers/of/unittest.c @@ -295,7 +295,7 @@ static void __init of_unittest_printf(void) return; } - num_to_str(phandle_str, sizeof(phandle_str), np->phandle); + num_to_str(phandle_str, sizeof(phandle_str), np->phandle, 0); of_unittest_printf_one(np, "%pOF", full_name); of_unittest_printf_one(np, "%pOFf", full_name); |