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[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: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
This commit is contained in:
Stephen Hemminger 2006-12-04 17:08:19 -08:00 committed by Jeff Garzik
parent 6771290102
commit c3905bc4b7
2 changed files with 9 additions and 3 deletions
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11
drivers/net/sky2.c
View File

@ -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);

1
drivers/net/sky2.h
View File

@ -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) */