From: Bernd Petrovitsch <bernd@petrovitsch.priv.at>
To: pavel@pavlinux.ru
Cc: LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] Repalce strncmp by memcmp
Date: Tue, 30 Nov 2010 11:34:20 +0100 [thread overview]
Message-ID: <1291113260.16068.13.camel@thorin> (raw)
In-Reply-To: <4CF30B46.4000203@pavlinux.ru>
On Mon, 2010-11-29 at 05:09 +0300, Pavel Vasilyev wrote:
> This patch replace all strncmp(a, b, c) by memcmp(a, b, c).
>
> I test on x86_64 (AMD Opteron 285).
>
> #include <string.h>
> char *A = "0000";
> void test_memcmp(void) {
> memcmp(A, "TEST", 4);
> }
> void test_strn(void) {
> strncmp(A, "TEST", 4);
> }
[...]
You use constant parameters with user-space functions defined by the
C-standard on one architecture (and CPU?) - and even worse the width is
4 so - for the memcmp() case - it boilsdown to a comparison of unsigned
ints.
So that example is (also) completely worthless.
Bernd
--
Bernd Petrovitsch Email : bernd@petrovitsch.priv.at
LUGA : http://www.luga.at
prev parent reply other threads:[~2010-11-30 10:34 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-11-29 2:09 [PATCH] Repalce strncmp by memcmp Pavel Vasilyev
2010-11-29 2:21 ` microcai
2010-11-29 2:29 ` Ming Lei
2010-11-29 3:11 ` Pavel Vasilyev
2010-11-29 4:13 ` Dmitry Torokhov
2010-11-29 5:26 ` YOSHIFUJI Hideaki
2010-11-29 12:41 ` Pavel Vasilyev
2010-11-29 3:10 ` Américo Wang
2010-11-29 10:18 ` Andi Kleen
2010-11-29 14:58 ` Steven Rostedt
2010-11-29 19:41 ` Pavel Vasilyev
2010-11-29 22:18 ` Steven Rostedt
2010-11-29 22:26 ` Steven Rostedt
2010-11-29 22:49 ` Pavel Vasilyev
2010-11-30 9:24 ` Américo Wang
2010-11-29 22:51 ` Ryan Mallon
2010-11-30 10:27 ` Bernd Petrovitsch
2010-11-29 23:32 ` Arnaud Lacombe
2010-11-30 10:34 ` Bernd Petrovitsch [this message]
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=1291113260.16068.13.camel@thorin \
--to=bernd@petrovitsch.priv.at \
--cc=linux-kernel@vger.kernel.org \
--cc=pavel@pavlinux.ru \
/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