Commit 452c447a authored Jul 25, 2013 by Ming Lei Committed by David S. Miller Jul 27, 2013

USBNET: increase max rx/tx qlen for improving USB3 thoughtput



The default RX_QLEN()/TX_QLEN() didn't consider super speed
USB device, so only max 4 URBs are scheduled at the same time
for tx/rx, then USB3 NIC can't perform very well.

With this patch, both rx and tx thoughput are increased more than
100Mbps when doing iperf test on ax88179_178a USB 3.0 NIC.

Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent a88c32ae

drivers/net/usb/usbnet.c

+9 −0

Original line number	Diff line number	Diff line
		@@ -355,6 +355,15 @@ void usbnet_update_max_qlen(struct usbnet *dev)
		dev->rx_qlen = MAX_QUEUE_MEMORY / dev->rx_urb_size;
		dev->tx_qlen = MAX_QUEUE_MEMORY / dev->hard_mtu;
		break;
		case USB_SPEED_SUPER:
		/*
		* Not take default 5ms qlen for super speed HC to
		* save memory, and iperf tests show 2.5ms qlen can
		* work well
		*/
		dev->rx_qlen = 5 * MAX_QUEUE_MEMORY / dev->rx_urb_size;
		dev->tx_qlen = 5 * MAX_QUEUE_MEMORY / dev->hard_mtu;
		break;
		default:
		dev->rx_qlen = dev->tx_qlen = 4;
		}

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