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From: Claudiu Manoil <claudiu.manoil@nxp.com>
To: Vladimir Oltean <olteanv@gmail.com>,
	Jakub Kicinski <kuba@kernel.org>,
	"David S. Miller" <davem@davemloft.net>,
	"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
	Po Liu <po.liu@nxp.com>
Cc: Alexandru Marginean <alexandru.marginean@nxp.com>,
	Rob Herring <robh+dt@kernel.org>, Shawn Guo <shawnguo@kernel.org>,
	"linux-arm-kernel@lists.infradead.org"
	<linux-arm-kernel@lists.infradead.org>,
	"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
	Russell King - ARM Linux admin <linux@armlinux.org.uk>,
	Andrew Lunn <andrew@lunn.ch>, Michael Walle <michael@walle.cc>,
	Vladimir Oltean <vladimir.oltean@nxp.com>
Subject: RE: [PATCH net-next 5/5] net: enetc: add support for flow control
Date: Mon, 19 Apr 2021 09:07:23 +0000
Message-ID: <AM0PR04MB6754B48B5F0C5B166783680696499@AM0PR04MB6754.eurprd04.prod.outlook.com> (raw)
In-Reply-To: <20210416234225.3715819-6-olteanv@gmail.com>



>-----Original Message-----
>From: Vladimir Oltean <olteanv@gmail.com>
>Sent: Saturday, April 17, 2021 2:42 AM
>To: Jakub Kicinski <kuba@kernel.org>; David S. Miller
><davem@davemloft.net>; netdev@vger.kernel.org; Po Liu
><po.liu@nxp.com>
>Cc: Claudiu Manoil <claudiu.manoil@nxp.com>; Alexandru Marginean
><alexandru.marginean@nxp.com>; Rob Herring <robh+dt@kernel.org>;
>Shawn Guo <shawnguo@kernel.org>; linux-arm-kernel@lists.infradead.org;
>devicetree@vger.kernel.org; Russell King - ARM Linux admin
><linux@armlinux.org.uk>; Andrew Lunn <andrew@lunn.ch>; Michael Walle
><michael@walle.cc>; Vladimir Oltean <vladimir.oltean@nxp.com>
>Subject: [PATCH net-next 5/5] net: enetc: add support for flow control
>
>From: Vladimir Oltean <vladimir.oltean@nxp.com>
>
>In the ENETC receive path, a frame received by the MAC is first stored
>in a 256KB 'FIFO' memory, then transferred to DRAM when enqueuing it to
>the RX ring. The FIFO is a shared resource for all ENETC ports, but
>every port keeps track of its own memory utilization, on RX and on TX.
>
>There is a setting for RX rings through which they can either operate in
>'lossy' mode (where the lack of a free buffer causes an immediate
>discard of the frame) or in 'lossless' mode (where the lack of a free
>buffer in the ring makes the frame stay longer in the FIFO).
>
>In turn, when the memory utilization of the FIFO exceeds a certain
>margin, the MAC can be configured to emit PAUSE frames.
>
>There is enough FIFO memory to buffer up to 3 MTU-sized frames per RX
>port while not jeopardizing the other use cases (jumbo frames), and
>also not consume bytes from the port TX allocations. Also, 3 MTU-sized
>frames worth of memory is enough to ensure zero loss for 64 byte packets
>at 1G line rate.
>
>Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>

Reviewed-by: Claudiu Manoil <claudiu.manoil@nxp.com>

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Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-16 23:42 [PATCH net-next 0/5] Flow control for NXP ENETC Vladimir Oltean
2021-04-16 23:42 ` [PATCH net-next 1/5] net: enetc: create a common enetc_pf_to_port helper Vladimir Oltean
2021-04-16 23:42 ` [PATCH net-next 2/5] dt-bindings: net: fsl: enetc: add the IERB documentation Vladimir Oltean
2021-04-16 23:42 ` [PATCH net-next 3/5] net: enetc: add a mini driver for the Integrated Endpoint Register Block Vladimir Oltean
2021-04-16 23:42 ` [PATCH net-next 4/5] arm64: dts: ls1028a: declare the Integrated Endpoint Register Block node Vladimir Oltean
2021-04-16 23:42 ` [PATCH net-next 5/5] net: enetc: add support for flow control Vladimir Oltean
2021-04-19  9:07   ` Claudiu Manoil [this message]
2021-04-19 21:04 ` [PATCH net-next 0/5] Flow control for NXP ENETC Jakub Kicinski
2021-04-19 21:49   ` Vladimir Oltean
2021-04-19 22:40 ` patchwork-bot+netdevbpf
2021-04-20 13:27 ` Michael Walle
2021-04-20 14:04   ` Vladimir Oltean
2021-04-20 14:10     ` Michael Walle
2021-04-20 14:16       ` Vladimir Oltean

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