Commit c3905bc4 authored by Stephen Hemminger's avatar Stephen Hemminger Committed by Jeff Garzik
Browse files

[PATCH] sky2: receive queue watermark tweak 



This patch makes the receive performance on some systems go from
714MB/s to 941MB/s. It adjusts the watermark of the receive queue
to be lower, thereby avoiding excess hardware flow control. This is
most important on the systems which have little/no additional buffering.

Signed-off-by: default avatarStephen Hemminger <shemminger@osdl.org>
Signed-off-by: default avatarJeff Garzik <jeff@garzik.org>
parent 67712901

drivers/net/sky2.c

+8 −3
Original line number Diff line number Diff line
@@ -1062,11 +1062,16 @@ static int sky2_rx_start(struct sky2_port *sky2) 
	sky2->rx_put = sky2->rx_next = 0;

	sky2_qset(hw, rxq);



	/* On PCI express lowering the watermark gives better performance */

	if (pci_find_capability(hw->pdev, PCI_CAP_ID_EXP))

		sky2_write32(hw, Q_ADDR(rxq, Q_WM), BMU_WM_PEX);



	/* These chips have no ram buffer?

	 * MAC Rx RAM Read is controlled by hardware */

	if (hw->chip_id == CHIP_ID_YUKON_EC_U &&

	    (hw->chip_rev == CHIP_REV_YU_EC_U_A1 || hw->chip_rev == CHIP_REV_YU_EC_U_B0)) {

		/* MAC Rx RAM Read is controlled by hardware */

	    (hw->chip_rev == CHIP_REV_YU_EC_U_A1

	     || hw->chip_rev == CHIP_REV_YU_EC_U_B0))

		sky2_write32(hw, Q_ADDR(rxq, Q_F), F_M_RX_RAM_DIS);

	}



	sky2_prefetch_init(hw, rxq, sky2->rx_le_map, RX_LE_SIZE - 1);

drivers/net/sky2.h

+1 −0
Original line number Diff line number Diff line
@@ -680,6 +680,7 @@ enum { 
			  BMU_FIFO_ENA | BMU_OP_ON,



	BMU_WM_DEFAULT = 0x600,

	BMU_WM_PEX     = 0x80,

};



/* Tx BMU Control / Status Registers (Yukon-2) */

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