From: Andrew Gallatin <gallatin@myri•com>
To: Ben Hutchings <bhutchings@solarflare•com>
Cc: David Miller <davem@davemloft•net>,
netdev@vger•kernel.org, linux-net-drivers@solarflare•com,
Eric Dumazet <eric.dumazet@gmail•com>,
Herbert Xu <herbert@gondor•hengli.com.au>
Subject: Re: [PATCH net-next] gro: Handle inline VLAN tags
Date: Fri, 16 Nov 2012 20:17:24 -0500 [thread overview]
Message-ID: <50A6E5A4.7060904@myri.com> (raw)
In-Reply-To: <1353097030.2743.28.camel@bwh-desktop.uk.solarflarecom.com>
On 11/16/12 15:17, Ben Hutchings wrote:
> The receive paths for skbs with inline and out-of-line VLAN tags (VLAN
> RX accleration) were made largely consistent in 2.6.37, with tags
> pulled out by software as necessary. However GRO doesn't do this, so
> it is not effective for VLAN-tagged packets received on devices
> without VLAN RX acceleration.
>
> napi_gro_frags() must not free the skb and does not advance the
> skb->data pointer, so cannot use vlan_untag(). Extract the core of
> vlan_untag() into a new function __vlan_untag() that allows the offset
> to the VLAN tag to be specified and returns an error code. Add
> kernel-doc comments for both those functions.
>
> Signed-off-by: Ben Hutchings <bhutchings@solarflare•com>
> ---
> Tested with sfc using both napi_gro_receive() and napi_gro_frags(). On
> a Core i7 920 (Nehalem) system it increased TCP/IPv4 receive throughput
> over a VLAN from ~8.0 to ~9.3 Gbit/s.
I verified similar results on myri10ge, using my recent GRO
patchset (minus the in-driver vtag removal) with just
napi_gro_frags().
I've no strong feeling as to whether or not this belongs in GRO or the
driver. I'm just glad that it is being discussed.
Thank you,
Drew
prev parent reply other threads:[~2012-11-17 1:17 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-11-16 20:17 [PATCH net-next] gro: Handle inline VLAN tags Ben Hutchings
2012-11-16 23:01 ` Eric Dumazet
2012-11-17 0:00 ` Ben Hutchings
2012-11-17 0:16 ` Eric Dumazet
2012-11-17 0:32 ` Ben Hutchings
2012-11-17 1:09 ` Eric Dumazet
2012-11-20 0:10 ` David Miller
2012-11-26 15:04 ` Andrew Gallatin
2012-11-28 16:46 ` David Miller
2012-11-28 17:30 ` Andrew Gallatin
2012-11-28 18:39 ` David Miller
2012-11-17 1:17 ` Andrew Gallatin [this message]
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