Subject: Re: GSO/GRO and UDP performance

From: Rick Jones <[email-masked]>
Date: Fri, 06 Sep 2013 09:42:17 -0700

On 09/06/2013 06:07 AM, Eric Dumazet wrote:
> On Fri, 2013-09-06 at 03:22 -0600, James Yonan wrote:
>
>> So I think that playing well with GSO/GRO is essential to get speedup in
>> UDP apps because of this 43x multiplier.
>>
>
> Thats not true. GRO cannot aggregate more than 16+1 packets.
>
> I think we cannot aggregate UDP packets, because UDP lacks sequence
> numbers, so reorders would be a problem.
>
> You really need something that is not UDP generic.

It may  not be as sexy, and it cannot get the 43x multiplier (just what 
*is* the service demand change on a netperf TCP_STREAM test these days 
between GSO/GRO on and off anyway?), but looking for basic path-length 
reductions would be goodness.

rick jones