Subject: Re: [PATCH net-next] packet: respect devices with LLTX flag in direct xmit

From: Daniel Borkmann <[email-masked]>
Date: Fri, 28 Mar 2014 22:13:40 +0100

On 03/28/2014 09:50 PM, David Miller wrote:
> From: Daniel Borkmann <[email-masked]>
> Date: Thu, 27 Mar 2014 16:38:30 +0100
>
>> Quite often it can be useful to test with dummy or similar
>> devices as a blackhole sink for skbs. Such devices are only
>> equipped with a single txq, but marked as NETIF_F_LLTX as
>> they do not require locking their internal queues on xmit
>> (or implement locking themselves). Therefore, rather use
>> HARD_TX_{UN,}LOCK API, so that NETIF_F_LLTX will be respected.
>>
>> trafgen mmap/TX_RING example against dummy device with config
>> foo: { fill(0xff, 64) } results in the following performance
>> improvements for such scenarios on an ordinary Core i7/2.80GHz:
>   ...
>> Signed-off-by: Daniel Borkmann <[email-masked]>
>> Cc: Jesper Dangaard Brouer <[email-masked]>
>
> Applied, nice work.
>
> The only remaining issue is that Eric seems to suggest that a tx
> dropped counter bump should be added.  Please submit that as a
> follow-on if my reading of his feedback is accurate.

Yes, will do next week. I think at time of submission we didn't
have that yet. :)