Subject: Re: [PATCH RFC net-next] vxlan: GRO support at tunnel layer

From: Rick Jones <[email-masked]>
Date: Fri, 26 Jun 2015 17:46:02 -0700

On 06/26/2015 04:09 PM, Tom Herbert wrote:
> Add calls to gro_cells infrastructure to do GRO when receiving on a tunnel.
>
> Testing:
>
> Ran 200 netperf TCP_STREAM instance
>
> - With fix (GRO enabled on VXLAN interface)
>
>    Verify GRO is happening.
>
>    9084 MBps tput
>    3.44% CPU utilization
>
> - Without fix (GRO disabled on VXLAN interface)
>
>    Verified no GRO is happening.
>
>    9084 MBps tput
>    5.54% CPU utilization

This has been an area of interest so:

Tested-by: Rick Jones <[email-masked]>

Some single-stream results between two otherwise identical systems with 
82599ES NICs in them, one running a 4.1.0-rc1+ kernel from a davem tree 
from a while ago, the other running 4.1.0+ from a davem tree pulled 
yesterday upon which I've applied the patch.

Netperf command used:

netperf -l 30 -H <IP> -t TCP_MAERTS -c -- -O 
throughput,local_cpu_util,local_cpu_peak_util,local_cpu_peak_id,local_sd

First, inbound to the unpatched system from the patched:

MIGRATED TCP MAERTS TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 
192.168.0.21 () port 0 AF_INET : demo
Throughput Local Local   Local   Local
            CPU   Peak    Peak    Service
            Util  Per CPU Per CPU Demand
            %     Util %  ID
5487.42    6.01  99.83   0       2.872
5580.83    6.20  99.16   0       2.911
5445.52    5.68  98.92   0       2.734
5653.36    6.24  99.80   0       2.891
5187.56    5.66  97.41   0       2.858

Second, inbound to the patched system from the unpatched:

MIGRATED TCP MAERTS TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 
192.168.0.22 () port 0 AF_INET : demo
Throughput Local Local   Local   Local
            CPU   Peak    Peak    Service
            Util  Per CPU Per CPU Demand
            %     Util %  ID
6933.29    3.19  93.67   3       1.208
7031.35    3.34  95.08   3       1.244
7006.28    3.27  94.55   3       1.223
6948.62    3.09  93.20   3       1.165
7007.80    3.22  94.34   3       1.206

Comparing the service demands shows a > 50% reduction in overhead.