netdev - Re: [RFC][PATCH] iproute: Faster ip link add, set and delete

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: <1364521138.15753.66.camel@edumazet-glaptop>
Date:	Thu, 28 Mar 2013 18:38:58 -0700
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	"Eric W. Biederman" <ebiederm@...ssion.com>
Cc:	Stephen Hemminger <stephen@...workplumber.org>,
	Benoit Lourdelet <blourdel@...iper.net>,
	Serge Hallyn <serge.hallyn@...ntu.com>,
	"netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: Re: [RFC][PATCH] iproute: Faster ip link add, set and delete

On Thu, 2013-03-28 at 18:29 -0700, Eric W. Biederman wrote:

> An interesting thought.  I had a patch I never got around to pushing a
> while back that would have had an effect.
> 
> It is my observation that the vast majority of packet filters apply not
> to the entire machine but to an individual interface.  In fact you have
> to work pretty hard to get tools like tcpdump to dump all of the
> interfaces at once.
> 
> So to speed things up for machines that have a lot of these things the
> idea was to create per device lists for the filters that only needed to
> be run on a single device.  In this case it looks like we could
> potentially create per device lists for of the listening sockets as well.
> 
> In general these lists should be short so the search can also be short.
> 
> But I am curious do you actually have a tcpdump or something similar
> running on your box that is using AF_PACKET sockets?  Perhaps a dhcp
> client?
> 
> I am a little surprised that your default case has anything on the lists
> to trigger any work in the packet_notifier notifier.

Hmm, it might be a local daemon on my lab machine which does a
PACKET_ADD_MEMBERSHIP for each created interface.

So my machine spend time in packet_dev_mclist(), with a quadratic
behavior at rmmod.



--
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