From: Willy Tarreau <w@1wt.eu>
To: David Miller <davem@davemloft.net>
Cc: eric.dumazet@gmail.com, ezequiel.garcia@free-electrons.com,
netdev@vger.kernel.org, thomas.petazzoni@free-electrons.com,
gregory.clement@free-electrons.com, simon.guinot@sequanux.org,
tawfik@marvell.com, alior@marvell.com
Subject: Re: [PATCH 0/3] mvneta: software TSO implementation
Date: Fri, 11 Apr 2014 08:30:21 +0200 [thread overview]
Message-ID: <20140411063021.GH30855@1wt.eu> (raw)
In-Reply-To: <20140411.022006.1718259701974368498.davem@davemloft.net>
On Fri, Apr 11, 2014 at 02:20:06AM -0400, David Miller wrote:
> From: Willy Tarreau <w@1wt.eu>
> Date: Fri, 11 Apr 2014 07:48:47 +0200
>
> > I also tried to find how to do this for mv643xx_eth a few years ago
> > based on other drivers (eg: tilegx) and failed to find anything
> > common. At this level, we're really playing with the NIC's descriptors,
> > and many of them have different capabilities (eg: HW checksums for all
> > frames, VLAN or none, etc...). I don't really see how this could be
> > factorized, and since many NICs do support TSO, I'm not convinced by
> > the effort.
>
> I wanted to hook this into the NIU driver as well, which also lacks
> TSO support.
>
> The descriptor and checksum part is chip specific, but the segmentation
> of the buffer segments, calculating the number of necessary descriptors,
> etc. absolutely is not.
Agreed.
> Please work on finding a suitable abstraction, it's possible.
Do you think for example that having an xmit_tso() function which would
iterate over all segments and call something like :
->build_hdr()
->build_data()
->unroll_all()
would be sufficient ?
I fear that relying on function pointers in the inner loop can
significantly offset the CPU savings, but it could be attempted.
I think that the fact you want to do it for NIU is a good opportunity
to try to do it the right way in the most generic mode, but we'll
surely need your help on this!
Willy
next prev parent reply other threads:[~2014-04-11 6:30 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-04-10 22:57 [PATCH 0/3] mvneta: software TSO implementation Ezequiel Garcia
2014-04-10 22:58 ` [PATCH 1/3] net: mvneta: Factorize feature setting Ezequiel Garcia
2014-04-10 22:58 ` [PATCH 2/3] net: mvneta: Clean mvneta_tx() sk_buff handling Ezequiel Garcia
2014-04-10 22:58 ` [PATCH 3/3] net: mvneta: Introduce a software TSO implementation Ezequiel Garcia
2014-04-10 23:16 ` Eric Dumazet
2014-05-05 14:47 ` Ezequiel Garcia
2014-05-07 6:04 ` Willy Tarreau
2014-05-21 2:11 ` Ben Hutchings
2014-05-22 17:47 ` Ezequiel Garcia
2014-04-11 0:51 ` [PATCH 0/3] mvneta: " David Miller
2014-04-11 1:02 ` Eric Dumazet
2014-04-11 5:48 ` Willy Tarreau
2014-04-11 6:20 ` David Miller
2014-04-11 6:30 ` Willy Tarreau [this message]
2014-04-11 16:58 ` David Miller
2014-04-11 19:08 ` Ezequiel Garcia
2014-04-11 19:43 ` Willy Tarreau
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