From mboxrd@z Thu Jan  1 00:00:00 1970
From: Benjamin LaHaise <bcrl@lhnet.ca>
Subject: Re: [PATCH] net: allow netdev_wait_allrefs() to run faster
Date: Mon, 9 Aug 2010 13:48:56 -0400
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Cc: "Eric W. Biederman" <ebiederm@xmission.com>,
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To: Ben Greear <greearb@candelatech.com>
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On Mon, Aug 09, 2010 at 10:44:14AM -0700, Ben Greear wrote:
> We also have a few rules per interface, and notice that it takes around 10ms
> per rule when we are removing them, even when using batching in 'ip':
...
> Patrick thought had an idea, but I don't think he had time to
> look at it further:
> 
> "Its probably the synchronize_rcu() in fib_nl_delrule() and
> the route flushing happening after rule removal."

Yes, that would be a problem, but the issue is deeper than that -- if I'm 
not mistaken it's on the packet processing path that iptables doesn't scale 
for 100k interfaces with 1 rule per interface.  It's been a while since I 
ran the tests, but I don't think it's changed much.

		-ben