MVEBU and MVNETA driver

[w@1wt.eu (Willy Tarreau)]

On Fri, Apr 19, 2013 at 06:02:19PM +0200, Greg wrote:
> A simple tool like netcat shows ~470Mbps but this limited by the CPU.
> Iperf isn't CPU limited
> 
> The same test with Marvell LSP shows ~940Mbps in both directions.

I've retested here on my mirabox using httpterm as the tcp server.
Using the normal send() syscall, it emits 839 Mbps on a single TCP
connection. Using splice(), it emits 969 Mbps in the same conditions.

Here's what ethtool is saying about the NIC's tuning :
# ethtool -k eth0
Offload parameters for eth0:
rx-checksumming: off
tx-checksumming: on
scatter-gather: on
tcp-segmentation-offload: off
udp-fragmentation-offload: off
generic-segmentation-offload: on
generic-receive-offload: on
large-receive-offload: off
rx-vlan-offload: off
tx-vlan-offload: off
ntuple-filters: off
receive-hashing: off

I've tried changing other settings such as the interrupt delays
(rx-usecs, rx-frames, tx-frames) but this has no effect. So in
short, I cannot reproduce this behaviour. Are you using the SLOB
allocator ? I'm asking because I remember experiencing very poor
performance with it in the past.

Regards,
Willy