netdev - Re: fedora 14 kernel performance with ip forwarding workload

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: <20110406201305.GF14697@ghostprotocols.net>
Date:	Wed, 6 Apr 2011 17:13:05 -0300
From:	Arnaldo Carvalho de Melo <acme@...stprotocols.net>
To:	David Miller <davem@...emloft.net>
Cc:	fedora-kernel-list@...hat.com, netdev@...r.kernel.org,
	jesse.brandeburg@...el.com, jesse.brandeburg@...il.com
Subject: Re: fedora 14 kernel performance with ip forwarding workload

Em Wed, Apr 06, 2011 at 01:02:39PM -0700, David Miller escreveu:
> From: Arnaldo Carvalho de Melo <acme@...stprotocols.net>
> Date: Wed, 6 Apr 2011 16:57:19 -0300
> 
> > Something like ftrace code changing when the user inserts the first
> > rule?
> > 
> > People wanting top performance disable it in the build, but thos wanting
> > to stick to vendor provided kernels don't have that choice :)
> 
> Using ftrace-like stubs would be an interesting idea, and I highly encourage
> people to work on something like that.

cool, these code modification and JIT mechanizms open up a lot of
possibilities indeed ;-)
 
> However I want to reiterate that I think that real rules are installed
> in Jesse's case, and once he removes those the majority of the
> overhead will disappear.  The FC14 workstation I'm using right now, on
>
> which I've made no modifications to the installer's netfilter settings,
> has the following rules:

<SNIP>
 
> I suspect Jesse has something similar on his test box.
> 
> When no rules are loaded, all the stubs make happen is a function call
> plus a list_empty() check.  Nothing more.  I really can't see that, all
> by itself, obliterating routing performance.

Yeah, would be nice, since he is playing with it, for him to post
numbers about the overheads.
 
> In fact I've done udp flood tests, as recently as a month ago, with just
> NETFILTER=y and no rules installed, and the impact was minimal.
> 
> And that was on sparc64 where function calls are expensive :)

:-)

- Arnaldo
--
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