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From: Ben Hutchings <bhutchings@solarflare.com>
To: Stephen Hemminger <shemminger@vyatta.com>
Cc: Yevgeny Petrilin <yevgenyp@mellanox.co.il>,
	Eric Dumazet <eric.dumazet@gmail.com>,
	"davem@davemloft.net" <davem@davemloft.net>,
	"netdev@vger.kernel.org" <netdev@vger.kernel.org>
Subject: Re: [PATCH 6/7] mlx4_en: Adding rxhash support
Date: Wed, 19 Oct 2011 15:57:08 +0100	[thread overview]
Message-ID: <1319036228.2829.14.camel@bwh-desktop> (raw)
In-Reply-To: <1318966500.2783.124.camel@bwh-desktop>

On Tue, 2011-10-18 at 20:35 +0100, Ben Hutchings wrote:
[...]
> There was also a proposal a while back that we should try to make the
> hash symmetric w.r.t. RX and TX addresses, so that both directions of a
> flow through a router/bridge are aligned.  I think this was to be done
> by repeating a 16-bit pattern across the key.  Not sure whether that's
> worthwhile.

That also makes it relatively cheap to calculate in software, which
DragonflyBSD does:

http://gitweb.dragonflybsd.org/dragonfly.git/blob/master:/sys/net/toeplitz.c
http://gitweb.dragonflybsd.org/dragonfly.git/blob/master:/sys/net/toeplitz2.h

(the latter file appears to assume that in_addr_t/in_port_t are byte-
swapped i.e. the host is little-endian).

Ben.

-- 
Ben Hutchings, Staff Engineer, Solarflare
Not speaking for my employer; that's the marketing department's job.
They asked us to note that Solarflare product names are trademarked.

      reply	other threads:[~2011-10-19 14:57 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-10-17 20:18 [PATCH 6/7] mlx4_en: Adding rxhash support Yevgeny Petrilin
2011-10-18  1:48 ` Eric Dumazet
2011-10-18  7:36   ` Yevgeny Petrilin
2011-10-18  8:34     ` Eric Dumazet
2011-10-18  8:59       ` Yevgeny Petrilin
2011-10-18 15:36         ` Stephen Hemminger
2011-10-18 18:49           ` Jesse Brandeburg
2011-10-18 19:05             ` Eric Dumazet
2011-10-18 19:35           ` Ben Hutchings
2011-10-19 14:57             ` Ben Hutchings [this message]

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