Subject: Re: [PATCH net-next] net: gro: add a per device gro flush timer

From: Rick Jones <[email-masked]>
Date: Thu, 06 Nov 2014 08:42:59 -0800

On 11/05/2014 06:39 PM, Eric Dumazet wrote:
> On Wed, 2014-11-05 at 18:14 -0800, Eric Dumazet wrote:
>> On Wed, 2014-11-05 at 17:38 -0800, Rick Jones wrote:
>>
>>> Speaking of QPS, what happens to 200 TCP_RR tests when the feature is
>>> enabled?
>
> The possible reduction of QPS happens when you have a single flow like
> TCP_RR  -- -r 40000,40000
>
> (Because we have one single TCP packet with 40000 bytes of payload,
> application is waked up once when Push flag is received)
>
> So cpu effiency is way better, but application has to copy 40000 bytes
> in one go _after_ Push flag, instead of being able to copy part of the
> data _before_ receiving the Push flag.

Thanks.  That isn't too unlike what I've seen happen in the past with 
say an 8K request size and switching back and forth between a 1500 and 
9000 byte MTU.

happy benchmarking,

rick