This patch saves elements on transmit ring by only updating the upper 64 bit address when it changes. With many workloads skb's are located in same region, so it saves space. Signed-off-by: Stephen Hemminger --- a/drivers/net/sky2.c 2009-08-18 09:32:29.143195273 -0700 +++ b/drivers/net/sky2.c 2009-08-18 09:33:15.490426779 -0700 @@ -1016,6 +1016,7 @@ static void tx_init(struct sky2_port *sk le = get_tx_le(sky2, &sky2->tx_prod); le->addr = 0; le->opcode = OP_ADDR64 | HW_OWNER; + sky2->tx_last_upper = 0; } static inline struct tx_ring_info *tx_le_re(struct sky2_port *sky2, @@ -1573,8 +1574,9 @@ static int sky2_xmit_frame(struct sk_buf struct sky2_tx_le *le = NULL; struct tx_ring_info *re; unsigned i, len; - u16 slot; dma_addr_t mapping; + u32 upper; + u16 slot; u16 mss; u8 ctrl; @@ -1593,9 +1595,11 @@ static int sky2_xmit_frame(struct sk_buf dev->name, slot, skb->len); /* Send high bits if needed */ - if (sizeof(dma_addr_t) > sizeof(u32)) { + upper = upper_32_bits(mapping); + if (upper != sky2->tx_last_upper) { le = get_tx_le(sky2, &slot); - le->addr = cpu_to_le32(upper_32_bits(mapping)); + le->addr = cpu_to_le32(upper); + sky2->tx_last_upper = upper; le->opcode = OP_ADDR64 | HW_OWNER; } @@ -1681,10 +1685,11 @@ static int sky2_xmit_frame(struct sk_buf if (pci_dma_mapping_error(hw->pdev, mapping)) goto mapping_unwind; - if (sizeof(dma_addr_t) > sizeof(u32)) { + upper = upper_32_bits(mapping); + if (upper != sky2->tx_last_upper) { le = get_tx_le(sky2, &slot); - le->addr = cpu_to_le32(upper_32_bits(mapping)); - le->ctrl = 0; + le->addr = cpu_to_le32(upper); + sky2->tx_last_upper = upper; le->opcode = OP_ADDR64 | HW_OWNER; } --- a/drivers/net/sky2.h 2009-08-18 09:29:59.224176503 -0700 +++ b/drivers/net/sky2.h 2009-08-18 09:33:15.491426771 -0700 @@ -2017,6 +2017,7 @@ struct sky2_port { u16 tx_pending; u16 tx_last_mss; + u32 tx_last_upper; u32 tx_tcpsum; struct rx_ring_info *rx_ring ____cacheline_aligned_in_smp; -- -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html