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

From: Russell King - ARM Linux admin <linux@armlinux.org.uk>
To: Stefan Chulski <stefanc@marvell.com>
Cc: Antoine Tenart <antoine.tenart@bootlin.com>,
	netdev <netdev@vger.kernel.org>,
	"gregory.clement@bootlin.com" <gregory.clement@bootlin.com>,
	"miquel.raynal@bootlin.com" <miquel.raynal@bootlin.com>,
	LKML <linux-kernel@vger.kernel.org>,
	Maxime Chevallier <maxime.chevallier@bootlin.com>,
	Nadav Haklai <nadavh@marvell.com>,
	Thomas Petazzoni <thomas.petazzoni@bootlin.com>,
	Matteo Croce <mcroce@redhat.com>, Marcin Wojtas <mw@semihalf.com>,
	"David S . Miller" <davem@davemloft.net>,
	Linux ARM <linux-arm-kernel@lists.infradead.org>
Subject: Re: [EXT] Re: [PATCH net-next 3/5] net: mvpp2: cls: Use RSS contexts to handle RSS tables
Date: Sat, 9 May 2020 14:25:24 +0100	[thread overview]
Message-ID: <20200509132524.GD1551@shell.armlinux.org.uk> (raw)
In-Reply-To: <DM5PR18MB11462564D691544445CA2A43B0A30@DM5PR18MB1146.namprd18.prod.outlook.com>

On Sat, May 09, 2020 at 12:31:21PM +0000, Stefan Chulski wrote:
> > -----Original Message-----
> > From: Matteo Croce <mcroce@redhat.com>
> > Sent: Saturday, May 9, 2020 3:16 PM
> > To: Stefan Chulski <stefanc@marvell.com>
> > Cc: David S . Miller <davem@davemloft.net>; Maxime Chevallier
> > <maxime.chevallier@bootlin.com>; netdev <netdev@vger.kernel.org>; LKML
> > <linux-kernel@vger.kernel.org>; Antoine Tenart
> > <antoine.tenart@bootlin.com>; Thomas Petazzoni
> > <thomas.petazzoni@bootlin.com>; gregory.clement@bootlin.com;
> > miquel.raynal@bootlin.com; Nadav Haklai <nadavh@marvell.com>; Marcin
> > Wojtas <mw@semihalf.com>; Linux ARM <linux-arm-
> > kernel@lists.infradead.org>; Russell King - ARM Linux admin
> > <linux@armlinux.org.uk>
> > 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.

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTC broadband for 0.8mile line in suburbia: sync at 10.2Mbps down 587kbps up

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