[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>
diff --git a/drivers/net/sky2.c b/drivers/net/sky2.c
index b9f7eb5..a8e0963 100644
--- a/drivers/net/sky2.c
+++ b/drivers/net/sky2.c
@@ -1062,11 +1062,16 @@
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);