stmmac: Performance regression after commit aff3d9eff843 "net: stmmac: enable multiple buffers"

[Corentin Labbe]

On Thu, Mar 23, 2017 at 10:12:18AM +0000, Joao Pinto wrote:
> 
> Hi Corentin,
> 
> Às 10:08 AM de 3/23/2017, Corentin Labbe escreveu:
> > Hello
> > 
> > Using next-20170323 produce a huge performance regression on my sunxi boards.
> > On dwmac-sun8i, iperf goes from 94mbs/s to 37 when sending.
> > 
> > On cubieboard2(dwmac-sunxi), iperf made the kernel flood with "ndesc_get_rx_status: Oversized frame spanned multiple buffers"
> > and network is lost after.
> > 
> > Reverting aff3d9eff84399e433c4aca65a9bb236581bc082 fix the issue.
> > I still try to found which part of this patch mades the performance lower.
> > 
> > Regards
> > Corentin Labbe
> > 
> 
> I have a 4.21 QoS Core with 4 RX + 4 TX and detected no regression.
> Could you please share the iperf cmds you are using in order for me to reproduce
> in my side?

simple iperf -c serverip for both board