From: Stephen Hemminger Date: Tue, 5 Dec 2006 01:08:19 +0000 (-0800) Subject: [PATCH] sky2: receive queue watermark tweak X-Git-Tag: v2.6.20-rc1~145^2^2~6^2~7 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c3905bc4b71ab562acf69765e8c4778bd263b9db;p=linux-2.6 [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 Signed-off-by: Jeff Garzik --- diff --git a/drivers/net/sky2.c b/drivers/net/sky2.c index b9f7eb5453..a8e096393a 100644 --- a/drivers/net/sky2.c +++ b/drivers/net/sky2.c @@ -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); diff --git a/drivers/net/sky2.h b/drivers/net/sky2.h index 7760545edb..a63f6057b2 100644 --- a/drivers/net/sky2.h +++ b/drivers/net/sky2.h @@ -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) */