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From: Stephen Hemminger <shemminger@vyatta.com>
To: Ben Hutchings <bhutchings@solarflare.com>
Cc: netdev@vger.kernel.org, linux-net-drivers@solarflare.com
Subject: Re: [RFC] [PATCH] net: Add support for ndo_select_queue() functions to cache the queue mapping
Date: Thu, 28 Jan 2010 10:00:11 -0800	[thread overview]
Message-ID: <20100128100011.2b624a9e@nehalam> (raw)
In-Reply-To: <1264700317.2783.15.camel@achroite.uk.solarflarecom.com>

On Thu, 28 Jan 2010 17:38:37 +0000
Ben Hutchings <bhutchings@solarflare.com> wrote:

> We think it's worth matching up RX and TX queue selection for a socket
> when the queues share an interrupt.  Currently the default TX queue
> selection is unlikely to match RX queue selection.  TX queue selectionc
> can be overridden by the driver to match RX queue selection, but at the
> expense of caching.  We found that without caching the cost of
> recalculating the the hash in software for each packet outweighed the
> benefit of good queue selection.

Will this work with RPS and device driver hashing?
I am thinking of the problem where the hardware hash function is
Toeplitz (per NDIS spec), and the software hash function is Jhash
(what kernel uses because it is cheaper).

Therefore the transmit hash and receiver hash will be different.


-- 

  reply	other threads:[~2010-01-28 18:00 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-01-28 17:38 [RFC] [PATCH] net: Add support for ndo_select_queue() functions to cache the queue mapping Ben Hutchings
2010-01-28 18:00 ` Stephen Hemminger [this message]
2010-01-28 18:34   ` Ben Hutchings
2010-02-04  1:47     ` David Miller
2010-01-28 18:09 ` Krishna Kumar2
2010-01-28 18:10   ` Ben Hutchings
2010-01-28 18:41     ` Krishna Kumar2
2010-01-28 18:40       ` Ben Hutchings
2010-01-28 19:04         ` Krishna Kumar2

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