Re: [EXT] Re: [PATCH net-next 3/5] net: mvpp2: cls: Use RSS contexts to handle RSS tables

[Russell King - ARM Linux admin]

On Sat, May 09, 2020 at 12:31:21PM +0000, Stefan Chulski wrote:
> > -----Original Message-----
> > From: Matteo Croce <mcroce@xxxxxxxxxx>
> > Sent: Saturday, May 9, 2020 3:16 PM
> > To: Stefan Chulski <stefanc@xxxxxxxxxxx>
> > Cc: David S . Miller <davem@xxxxxxxxxxxxx>; Maxime Chevallier
> > <maxime.chevallier@xxxxxxxxxxx>; netdev <netdev@xxxxxxxxxxxxxxx>; LKML
> > <linux-kernel@xxxxxxxxxxxxxxx>; Antoine Tenart
> > <antoine.tenart@xxxxxxxxxxx>; Thomas Petazzoni
> > <thomas.petazzoni@xxxxxxxxxxx>; gregory.clement@xxxxxxxxxxx;
> > miquel.raynal@xxxxxxxxxxx; Nadav Haklai <nadavh@xxxxxxxxxxx>; Marcin
> > Wojtas <mw@xxxxxxxxxxxx>; Linux ARM <linux-arm-
> > kernel@xxxxxxxxxxxxxxxxxxx>; Russell King - ARM Linux admin
> > <linux@xxxxxxxxxxxxxxx>
> > Subject: Re: [EXT] Re: [PATCH net-next 3/5] net: mvpp2: cls: Use RSS contexts to
> > handle RSS tables
> > 
> > Hi,
> > 
> > The point is that RXHASH works fine on all interfaces, but on the gigabit one
> > (eth2 usually).
> > And on the 10 gbit interface is very very effective, the throughput goes 4x when
> > enabled, so it would be a big drawback to disable it on all interfaces.
> > 
> > Honestly I don't have any 2.5 gbit hardware to test it on eth3, so I don't know if
> > rxhash actually only works on the first interface of a unit (so eth0 and eth1), or
> > if it just doesn't work on the gigabit one.
> > 
> > If someone could test it on the 2.5 gbit port, this will be helpful.
> 
> RSS tables is part of Packet Processor IP, not MAC(so it's not related to specific speed). Probably issue exist on specific packet processor ports.
> Since RSS work fine on first port of the CP, we can do the following:
> if (port-> id == 0)
> 	dev->hw_features |= NETIF_F_RXHASH;

I can confirm that Macchiatobin Single Shot eth0 port works with a
1G Fibre SFP or 10G DA SFP with or without rxhash on.

So it seems Stefan's hunch that it is port related is correct.

-- 
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