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From: Jakub Kicinski <kuba@kernel.org>
To: Cedric Jehasse via B4 Relay
	<devnull+cedric.jehasse.luminex.be@kernel.org>
Cc: cedric.jehasse@luminex.be, "Andrew Lunn" <andrew@lunn.ch>,
	"Vladimir Oltean" <olteanv@gmail.com>,
	"David S. Miller" <davem@davemloft.net>,
	"Eric Dumazet" <edumazet@google.com>,
	"Paolo Abeni" <pabeni@redhat.com>,
	"Simon Horman" <horms@kernel.org>,
	"Russell King" <linux@armlinux.org.uk>,
	"Jamal Hadi Salim" <jhs@mojatatu.com>,
	"Jiri Pirko" <jiri@resnulli.us>,
	"Vinicius Costa Gomes" <vinicius.gomes@intel.com>,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
	"Luke Howard" <lukeh@padl.com>, "Marek Behún" <kabel@kernel.org>,
	"Cedric Jehasse" <cedric.jehasse@gmail.com>
Subject: Re: [PATCH net-next v8 2/3] net: dsa: mv88e6xxx: use the hw tx queues
Date: Mon, 17 Aug 2026 10:50:24 -0700	[thread overview]
Message-ID: <20260817105024.65be6d55@kernel.org> (raw)
In-Reply-To: <20260811-net-next-mv88e6xxx-cbs-v8-2-10d0baab2905@luminex.be>

On Tue, 11 Aug 2026 13:45:48 +0200 Cedric Jehasse via B4 Relay wrote:
> When transmitting fill in the PRI field in the dsa tag to select the
> egress queue is sent to.
> From the datasheets i've looked at these switches have 4 or 8 transmit
> queues per port.
> Note: skbs with skb->offload_fwd_mark set use the DSA_CMD_FORWARD
> tag. These are processed as normal ingress frames, meaning the queue
> they end up in can still be altered by other switch config. eg. priority
> overrides, tcam policies.
> This isn't done for vlan tagged frames because this would overwrite the
> PCP value in the vlan tag (The PRI field in the dsa
> tag is used as the PCP value in the vlan tag).

Pretending that a DSA device has multiple Tx queues _from the stack_
makes no sense. You should be offloading PRIO as the root qdisc,
like mlxsw does. Then the rate limiters should be attached as children
of PRIO.

  reply	other threads:[~2026-08-17 17:50 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-08-11 11:45 [PATCH net-next v8 0/3] net: dsa: mv88e6xxx: add support for credit based shaper Cedric Jehasse via B4 Relay
2026-08-11 11:45 ` [PATCH net-next v8 1/3] net/sched: cbs: add extack to struct tc_cbs_qopt_offload Cedric Jehasse via B4 Relay
2026-08-11 11:45 ` [PATCH net-next v8 2/3] net: dsa: mv88e6xxx: use the hw tx queues Cedric Jehasse via B4 Relay
2026-08-17 17:50   ` Jakub Kicinski [this message]
2026-08-11 11:45 ` [PATCH net-next v8 3/3] net: dsa: mv88e6xxx: add support for credit based shaper Cedric Jehasse via B4 Relay
2026-08-17 17:45   ` Jakub Kicinski

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