From mboxrd@z Thu Jan  1 00:00:00 1970
From: Eric Dumazet <eric.dumazet@gmail.com>
Subject: Re: why all packets have same queue no when rps enabled?
Date: Tue, 22 Feb 2011 14:01:58 +0100
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Cc: Jon Zhou <Jon.Zhou@jdsu.com>,
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To: Ben Hutchings <bhutchings@solarflare.com>
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Le mardi 22 f=C3=A9vrier 2011 =C3=A0 12:45 +0000, Ben Hutchings a =C3=A9=
crit :

> The queue number identifies a hardware queue.  RPS therefore does not
> update this number when queueing packets for processing on other CPUs=
=2E
>=20
> If the hardware/driver provides a receive hash (probably Toeplitz) th=
en
> this is used for RPS.  Otherwise a much cheaper hash is used.

The default is/should be : rxhash generated in network stack.

ethtool -k eth0 | grep hash
receive-hashing: off

To use the device/harwdare provided rxhash, you need to ask for it.

ethtool -K eth0 rxhash on



BTW, I am not sure what you mean by "much cheaper hash is used"...

I presume hardware provided hash is less expensive (for our cpu) than
computing our rxhash...