netdev - Re: alignment faults in 3.6

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]

Date:	Fri, 12 Oct 2012 11:00:45 -0400
From:	Benjamin LaHaise <bcrl@...ck.org>
To:	Eric Dumazet <eric.dumazet@...il.com>
Cc:	Russell King - ARM Linux <linux@....linux.org.uk>,
	Måns Rullgård <mans@...sr.com>,
	Arnd Bergmann <arnd@...db.de>,
	linux-arm-kernel@...ts.infradead.org,
	David Laight <David.Laight@...lab.com>, netdev@...r.kernel.org,
	Jon Masters <jonathan@...masters.org>
Subject: Re: alignment faults in 3.6

On Fri, Oct 12, 2012 at 04:48:20PM +0200, Eric Dumazet wrote:
> > Somehow, I doubt anyone would be willing to walk through all the noise the 
> > faults would likely trigger.
> 
> If this can be mapped to an event that can be used by perf tool, that
> might be useful ?

There are performance counters for the various different types of alignment 
faults supported by perf. Modern x86 makes the vast majority of unaligned 
accesses very low overhead -- the only ones that really hurt are those 
straddling different vm pages, but even those have little cost compared to 
obsolete microarchitectures (*cough* P4 *cough*).

		-ben
-- 
"Thought is the essence of where you are now."
--
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