From: Al Viro <viro@ZenIV.linux.org.uk>
To: Alexey Dobriyan <adobriyan@gmail.com>
Cc: akpm@linux-foundation.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] proc: much faster /proc/vmstat
Date: Sun, 7 Aug 2016 02:35:13 +0100 [thread overview]
Message-ID: <20160807013510.GM2356@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20160806125455.GA1187@p183.telecom.by>
On Sat, Aug 06, 2016 at 03:54:56PM +0300, Alexey Dobriyan wrote:
[sprintf sucks, let's convert numbers manually]
> --- a/mm/vmstat.c
> +++ b/mm/vmstat.c
> @@ -1592,7 +1592,10 @@ static int vmstat_show(struct seq_file *m, void *arg)
> {
> unsigned long *l = arg;
> unsigned long off = l - (unsigned long *)m->private;
> - seq_printf(m, "%s %lu\n", vmstat_text[off], *l);
> +
> + seq_puts(m, vmstat_text[off]);
> + seq_put_decimal_ull(m, ' ', *l);
> + seq_putc(m, '\n');
> return 0;
> }
If that manages to be a hotspot, we really should
* educate the wankers responsible for the userland code in question,
until they repent and cease committing such abominations.
* look into fixing vsnprintf().
Seriously, what the hell is vsnprintf() doing that takes so much time? It's
not as if it was a complex format anyway. WTF is going on there? Where is
it spending that much time?
next prev parent reply other threads:[~2016-08-07 1:35 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-06 12:54 [PATCH] proc: much faster /proc/vmstat Alexey Dobriyan
2016-08-07 1:35 ` Al Viro [this message]
2016-08-07 8:42 ` Alexey Dobriyan
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