netdev - Re: bridge: faster compare for link local addresses

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20070313.123954.21595557.davem@davemloft.net>
Date:	Tue, 13 Mar 2007 12:39:54 -0700 (PDT)
From:	David Miller <davem@...emloft.net>
To:	dada1@...mosbay.com
Cc:	andi@...stfloor.org, rick.jones2@...com,
	shemminger@...ux-foundation.org, netdev@...r.kernel.org
Subject: Re: bridge: faster compare for link local addresses

From: Eric Dumazet <dada1@...mosbay.com>
Date: Tue, 13 Mar 2007 14:38:32 +0100

> But memcmp() has a strong semantic (in libc). memcmp(a, b, 6) should
> do 6 byte compares and conditional branches, regardless of a/b
> alignment.  Or use the x86 "rep cmpsb" instruction that basically
> has the same cost.

Yep, that's the issue, gcc won't make the reductions necessary
here to get it down to one comparison and one branch.
-
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html