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Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni Cc: Ovidiu Panait , netdev@vger.kernel.org, linux-kernel@vger.kernel.org References: <20260612205915.3156127-1-nb@tipi-net.de> <20260612205915.3156127-2-nb@tipi-net.de> Content-Language: en-US From: Justin Chen In-Reply-To: <20260612205915.3156127-2-nb@tipi-net.de> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-DetectorID-Processed: b00c1d49-9d2e-4205-b15f-d015386d3d5e On 6/12/26 1:59 PM, Nicolai Buchwitz wrote: > The strict-priority TX queues can starve under multi-queue load and > trip NETDEV_WATCHDOG. Justin's earlier series [1] worked around the > symptom but kept the design. > > The multi-queue design was originally used for STB use cases that are > no longer needed, as confirmed by Justin. v1 hw_params already > exercises a single-queue path. Point v2-v4 at the same configuration: > ring 0 takes the full BD pool, every per-ring loop collapses to one > iteration, and netif_set_real_num_tx_queues drops to 1 via the > existing tx_queues + 1 arithmetic. > > Tested on Raspberry Pi CM4 (BCM2711). The baseline kernel trips > NETDEV_WATCHDOG within seconds under iperf3 UDP saturation > (-u -b0 -P16 -t60). After the change the same test completes > without a watchdog, and a single-stream 60 s UDP run sustains > 956 Mbit/s with 0/4952890 datagrams lost. Single-stream TCP > throughput is unchanged at 943 Mbit/s. > > [1] https://lore.kernel.org/netdev/20260406175756.134567-1-justin.chen@broadcom.com/ > > Signed-off-by: Nicolai Buchwitz Reviewed-by: Justin Chen Tested-by: Justin Chen