From: Andrei Vagin <avagin@openvz.org>
To: linux-fsdevel@vger.kernel.org, Andrew Morton <akpm@linux-foundation.org>
Cc: Alexey Dobriyan <adobriyan@gmail.com>,
Andrei Vagin <avagin@openvz.org>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Subject: [PATCH 2/4] proc: replace seq_printf on seq_putc to speed up /proc/pid/smaps
Date: Sun, 11 Feb 2018 23:49:29 -0800 [thread overview]
Message-ID: <20180212074931.7227-2-avagin@openvz.org> (raw)
In-Reply-To: <20180212074931.7227-1-avagin@openvz.org>
seq_putc() works much faster than seq_printf()
$ time python test_smaps.py
== Before patch ==
real 0m3.828s
user 0m0.413s
sys 0m3.408s
== After patch ==
real 0m3.405s
user 0m0.401s
sys 0m3.003s
== Before 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_aligned
+ 19.78% __walk_page_range
+ 12.74% seq_printf
+ 11.08% show_map_vma.isra.23
+ 1.68% seq_puts
== After patch ==
- 69.16% 5.70% python [kernel.kallsyms] [k] show_smap.isra.33
- 63.46% show_smap.isra.33
+ 25.98% seq_put_decimal_ull_aligned
+ 20.90% __walk_page_range
+ 12.60% show_map_vma.isra.23
1.56% seq_putc
+ 1.55% seq_puts
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrei Vagin <avagin@openvz.org>
---
fs/proc/task_mmu.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 3026feda0432..65ae54659833 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -688,8 +688,9 @@ static void show_smap_vma_flags(struct seq_file *m, struct vm_area_struct *vma)
if (!mnemonics[i][0])
continue;
if (vma->vm_flags & (1UL << i)) {
- seq_printf(m, "%c%c ",
- mnemonics[i][0], mnemonics[i][1]);
+ seq_putc(m, mnemonics[i][0]);
+ seq_putc(m, mnemonics[i][1]);
+ seq_putc(m, ' ');
}
}
seq_putc(m, '\n');
--
2.13.6
next prev parent reply other threads:[~2018-02-12 7:49 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-12 7:49 [PATCH 1/4 v2] proc: add seq_put_decimal_ull_width to speed up /proc/pid/smaps Andrei Vagin
2018-02-12 7:49 ` Andrei Vagin [this message]
2018-02-12 14:10 ` [PATCH 2/4] proc: replace seq_printf on seq_putc " Alexey Dobriyan
2018-02-12 7:49 ` [PATCH 3/4] proc: optimize single-symbol delimiters to spead up seq_put_decimal_ull Andrei Vagin
2018-02-12 7:49 ` [PATCH 4/4] proc: replace seq_printf by seq_put_smth to speed up /proc/pid/status Andrei Vagin
-- strict thread matches above, loose matches on Subject: below --
2018-01-29 8:00 [PATCH 1/4] proc: add seq_put_decimal_ull_align to speed up /proc/pid/smaps Andrei Vagin
2018-01-29 8:00 ` [PATCH 2/4] proc: replace seq_printf on seq_putc " Andrei Vagin
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