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
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