From: Joe Perches <joe@perches.com>
To: Alexey Dobriyan <adobriyan@gmail.com>, akpm@linux-foundation.org
Cc: linux-kernel@vger.kernel.org
Subject: Re: [PATCH] proc: faster /proc/*/status
Date: Sat, 06 Aug 2016 15:41:34 -0700 [thread overview]
Message-ID: <1470523294.28648.33.camel@perches.com> (raw)
In-Reply-To: <20160806125608.GB1187@p183.telecom.by>
On Sat, 2016-08-06 at 15:56 +0300, Alexey Dobriyan wrote:
> top(1) opens the following files for every PID:
>
> /proc/*/stat
> /proc/*/statm
> /proc/*/status
>
> This patch switches /proc/*/status away from seq_printf().
> The result is 13.5% speedup.
If this is really an important consideration, perhaps
seq_put_decimal_ull (_ll too) should be changed from
void seq_put_decimal_ull(seq_file *, char, unsigned long long)
to
void seq_put_decimal_ull(seq_file *, const char *, unsigned long)
> fs/proc/array.c | 87 ++++++++++++++++++++++++++++++--------------------------
[]
> @@ -186,51 +186,52 @@ 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\n"
> - "Tgid:\t%d\n"
> - "Ngid:\t%d\n"
> - "Pid:\t%d\n"
> - "PPid:\t%d\n"
> - "TracerPid:\t%d\n"
> - "Uid:\t%d\t%d\t%d\t%d\n"
> - "Gid:\t%d\t%d\t%d\t%d\n"
> - "FDSize:\t%d\nGroups:\t",
> - get_task_state(p),
> - tgid, ngid, pid_nr_ns(pid, ns), ppid, tpid,
> - from_kuid_munged(user_ns, cred->uid),
> - from_kuid_munged(user_ns, cred->euid),
> - from_kuid_munged(user_ns, cred->suid),
> - from_kuid_munged(user_ns, cred->fsuid),
> - from_kgid_munged(user_ns, cred->gid),
> - from_kgid_munged(user_ns, cred->egid),
> - from_kgid_munged(user_ns, cred->sgid),
> - from_kgid_munged(user_ns, cred->fsgid),
> - max_fds);
> -
> + seq_printf(m, "State:\t%s", get_task_state(p));
> +
> + seq_puts(m, "\nTgid:\t");
> + seq_put_decimal_ull(m, 0, tgid);
[etc...]
Perhaps too the conversions from %d to %llu are inappropriate
and seq_put_decimal and seq_put_decimal_u should be added.
next prev parent reply other threads:[~2016-08-06 22:41 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-06 12:56 [PATCH] proc: faster /proc/*/status Alexey Dobriyan
2016-08-06 22:41 ` Joe Perches [this message]
2016-08-09 3:02 ` [PATCH] seq/proc: Modify seq_put_decimal_[u]ll to take a const char *, not char Joe Perches
2016-08-07 3:16 ` [PATCH] proc: faster /proc/*/status Andi Kleen
2016-08-07 8:53 ` Alexey Dobriyan
2016-08-07 16:59 ` Andi Kleen
2016-08-07 17:39 ` Joe Perches
2016-08-07 17:44 ` Andi Kleen
2016-08-07 21:22 ` Joe Perches
2016-08-09 23:25 ` Andrew Morton
2016-08-10 6:38 ` [RFC PATCH] meminfo: Break apart a very long seq_printf with #ifdefs Joe Perches
2016-08-11 21:50 ` Andrew Morton
2016-08-11 21:57 ` Joe Perches
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=1470523294.28648.33.camel@perches.com \
--to=joe@perches.com \
--cc=adobriyan@gmail.com \
--cc=akpm@linux-foundation.org \
--cc=linux-kernel@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.