From mboxrd@z Thu Jan 1 00:00:00 1970 From: Florian Westphal Subject: [PATCH next] net: e1000: support txtd update delay via xmit_more Date: Tue, 6 Jan 2015 16:16:59 +0100 Message-ID: <1420557419-18869-1-git-send-email-fw@strlen.de> Cc: Florian Westphal To: Return-path: Received: from Chamillionaire.breakpoint.cc ([80.244.247.6]:40355 "EHLO Chamillionaire.breakpoint.cc" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754388AbbAFPRG (ORCPT ); Tue, 6 Jan 2015 10:17:06 -0500 Sender: netdev-owner@vger.kernel.org List-ID: Don't update tx tail descriptor if we queue hasn't been stopped and we know at least one more skb will be sent right away. Signed-off-by: Florian Westphal --- drivers/net/ethernet/intel/e1000/e1000_main.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/drivers/net/ethernet/intel/e1000/e1000_main.c b/drivers/net/ethernet/intel/e1000/e1000_main.c index 83140cb..714b727 100644 --- a/drivers/net/ethernet/intel/e1000/e1000_main.c +++ b/drivers/net/ethernet/intel/e1000/e1000_main.c @@ -2977,7 +2977,6 @@ static void e1000_tx_queue(struct e1000_adapter *adapter, struct e1000_tx_ring *tx_ring, int tx_flags, int count) { - struct e1000_hw *hw = &adapter->hw; struct e1000_tx_desc *tx_desc = NULL; struct e1000_tx_buffer *buffer_info; u32 txd_upper = 0, txd_lower = E1000_TXD_CMD_IFCS; @@ -3031,11 +3030,6 @@ static void e1000_tx_queue(struct e1000_adapter *adapter, wmb(); tx_ring->next_to_use = i; - writel(i, hw->hw_addr + tx_ring->tdt); - /* we need this if more than one processor can write to our tail - * at a time, it synchronizes IO on IA64/Altix systems - */ - mmiowb(); } /* 82547 workaround to avoid controller hang in half-duplex environment. @@ -3263,6 +3257,14 @@ static netdev_tx_t e1000_xmit_frame(struct sk_buff *skb, /* Make sure there is space in the ring for the next send. */ e1000_maybe_stop_tx(netdev, tx_ring, MAX_SKB_FRAGS + 2); + if (!skb->xmit_more || + netif_xmit_stopped(netdev_get_tx_queue(netdev, 0))) { + writel(tx_ring->next_to_use, hw->hw_addr + tx_ring->tdt); + /* we need this if more than one processor can write to our tail + * at a time, it synchronizes IO on IA64/Altix systems + */ + mmiowb(); + } } else { dev_kfree_skb_any(skb); tx_ring->buffer_info[first].time_stamp = 0; -- 2.0.5