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>
Subject: [PATCH 4/4] proc: replace seq_printf by seq_put_smth to speed up /proc/pid/status
Date: Sun, 11 Feb 2018 23:49:31 -0800 [thread overview]
Message-ID: <20180212074931.7227-4-avagin@openvz.org> (raw)
In-Reply-To: <20180212074931.7227-1-avagin@openvz.org>
seq_printf() works slower than seq_puts, seq_puts, etc.
== test_proc.c
int main(int argc, char **argv)
{
int n, i, fd;
char buf[16384];
n = atoi(argv[1]);
for (i = 0; i < n; i++) {
fd = open(argv[2], O_RDONLY);
if (fd < 0)
return 1;
if (read(fd, buf, sizeof(buf)) <= 0)
return 1;
close(fd);
}
return 0;
}
==
$ time ./test_proc 1000000 /proc/1/status
== Before path ==
real 0m5.171s
user 0m0.328s
sys 0m4.783s
== After patch ==
real 0m4.761s
user 0m0.334s
sys 0m4.366s
Signed-off-by: Andrei Vagin <avagin@openvz.org>
---
fs/proc/array.c | 16 +++++++++++-----
1 file changed, 11 insertions(+), 5 deletions(-)
diff --git a/fs/proc/array.c b/fs/proc/array.c
index 598803576e4c..0a61affe1356 100644
--- a/fs/proc/array.c
+++ b/fs/proc/array.c
@@ -187,7 +187,8 @@ static inline void task_state(struct seq_file *m, struct pid_namespace *ns,
task_unlock(p);
rcu_read_unlock();
- seq_printf(m, "State:\t%s", get_task_state(p));
+ seq_puts(m, "State:\t");
+ seq_puts(m, get_task_state(p));
seq_put_decimal_ull(m, "\nTgid:\t", tgid);
seq_put_decimal_ull(m, "\nNgid:\t", ngid);
@@ -313,8 +314,8 @@ static void render_cap_t(struct seq_file *m, const char *header,
seq_puts(m, header);
CAP_FOR_EACH_U32(__capi) {
- seq_printf(m, "%08x",
- a->cap[CAP_LAST_U32 - __capi]);
+ seq_put_hex_ll(m, NULL,
+ a->cap[CAP_LAST_U32 - __capi], 8);
}
seq_putc(m, '\n');
}
@@ -368,7 +369,8 @@ static void task_cpus_allowed(struct seq_file *m, struct task_struct *task)
static inline void task_core_dumping(struct seq_file *m, struct mm_struct *mm)
{
- seq_printf(m, "CoreDumping:\t%d\n", !!mm->core_state);
+ seq_put_decimal_ull(m, "CoreDumping:\t", !!mm->core_state);
+ seq_putc(m, '\n');
}
int proc_pid_status(struct seq_file *m, struct pid_namespace *ns,
@@ -504,7 +506,11 @@ static int do_task_stat(struct seq_file *m, struct pid_namespace *ns,
/* convert nsec -> ticks */
start_time = nsec_to_clock_t(task->real_start_time);
- seq_printf(m, "%d (%s) %c", pid_nr_ns(pid, ns), tcomm, state);
+ seq_put_decimal_ull(m, "", pid_nr_ns(pid, ns));
+ seq_puts(m, " (");
+ seq_puts(m, tcomm);
+ seq_puts(m, ") ");
+ seq_putc(m, state);
seq_put_decimal_ll(m, " ", ppid);
seq_put_decimal_ll(m, " ", pgid);
seq_put_decimal_ll(m, " ", sid);
--
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 ` [PATCH 2/4] proc: replace seq_printf on seq_putc " Andrei Vagin
2018-02-12 14:10 ` 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 ` Andrei Vagin [this message]
-- 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 4/4] proc: replace seq_printf by seq_put_smth to speed up /proc/pid/status Andrei Vagin
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20180212074931.7227-4-avagin@openvz.org \
--to=avagin@openvz.org \
--cc=adobriyan@gmail.com \
--cc=akpm@linux-foundation.org \
--cc=linux-fsdevel@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).