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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.