netdev - Re: htb parallelism on multi-core platforms

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Date:	Wed, 29 Apr 2009 15:38:11 +0200
From:	Jarek Poplawski <jarkao2@...il.com>
To:	Radu Rendec <radu.rendec@...s.ro>
Cc:	Jesper Dangaard Brouer <hawk@...u.dk>,
	Denys Fedoryschenko <denys@...p.net.lb>,
	netdev <netdev@...r.kernel.org>,
	Calin Velea <calin.velea@...enii.ro>
Subject: Re: htb parallelism on multi-core platforms

On Wed, Apr 29, 2009 at 04:15:51PM +0300, Radu Rendec wrote:
...
> I've just had a look at Calin's approach to optimizing u32 lookups. It
> does indeed make a very nice use of u32 hash capabilities, resulting in
> a maximum of 4 lookups. The algorithm he uses takes advantage of the
> fact that only a (small) subset of the whole ipv4 address space is
> actually used in an ISP's network.
...

Anyway, it looks like your main problem, and I doubt even dividing
current work by e.g. 4 cores (if it were multi-threaded) is enough.
These lookups are simply too long.

> > Btw. #2: I think you wrote you didn't use iptables...
> No, I don't use iptables.

But your oprofile shows them. Maybe you shouldn't compile it into
kernel at all?

> 
> Btw, the e1000e driver seems to have no way to disable NAPI. Am I
> missing something (like a global kernel config option that disables NAPI
> completely)?

Calin uses older kernel, and maybe e1000 driver, I don't know.

Jarek P.
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