From: Peter P Waskiewicz Jr Date: Sat, 7 Feb 2009 05:47:24 +0000 (-0800) Subject: ixgbe: Defeature Tx Head writeback X-Git-Tag: v2.6.30-rc1~662^2~804 X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=12207e498b9b8f9f0c946db079ad17c7ca16cdf3;p=karo-tx-linux.git ixgbe: Defeature Tx Head writeback Tx Head writeback is causing multi-microsecond stalls on PCIe chipsets, due to partial cacheline writebacks. Removing this feature removes these issues. Signed-off-by: Peter P Waskiewicz Jr Signed-off-by: Jeff Kirsher Signed-off-by: David S. Miller --- diff --git a/drivers/net/ixgbe/ixgbe_main.c b/drivers/net/ixgbe/ixgbe_main.c index 850361a4c38d..8e270b63e806 100644 --- a/drivers/net/ixgbe/ixgbe_main.c +++ b/drivers/net/ixgbe/ixgbe_main.c @@ -204,9 +204,6 @@ static inline bool ixgbe_check_tx_hang(struct ixgbe_adapter *adapter, #define DESC_NEEDED (TXD_USE_COUNT(IXGBE_MAX_DATA_PER_TXD) /* skb->data */ + \ MAX_SKB_FRAGS * TXD_USE_COUNT(PAGE_SIZE) + 1) /* for context */ -#define GET_TX_HEAD_FROM_RING(ring) (\ - *(volatile u32 *) \ - ((union ixgbe_adv_tx_desc *)(ring)->desc + (ring)->count)) static void ixgbe_tx_timeout(struct net_device *netdev); /** @@ -217,26 +214,27 @@ static void ixgbe_tx_timeout(struct net_device *netdev); static bool ixgbe_clean_tx_irq(struct ixgbe_adapter *adapter, struct ixgbe_ring *tx_ring) { - union ixgbe_adv_tx_desc *tx_desc; - struct ixgbe_tx_buffer *tx_buffer_info; struct net_device *netdev = adapter->netdev; - struct sk_buff *skb; - unsigned int i; - u32 head, oldhead; - unsigned int count = 0; + union ixgbe_adv_tx_desc *tx_desc, *eop_desc; + struct ixgbe_tx_buffer *tx_buffer_info; + unsigned int i, eop, count = 0; unsigned int total_bytes = 0, total_packets = 0; - rmb(); - head = GET_TX_HEAD_FROM_RING(tx_ring); - head = le32_to_cpu(head); i = tx_ring->next_to_clean; - while (1) { - while (i != head) { + eop = tx_ring->tx_buffer_info[i].next_to_watch; + eop_desc = IXGBE_TX_DESC_ADV(*tx_ring, eop); + + while ((eop_desc->wb.status & cpu_to_le32(IXGBE_TXD_STAT_DD)) && + (count < tx_ring->count)) { + bool cleaned = false; + for ( ; !cleaned; count++) { + struct sk_buff *skb; tx_desc = IXGBE_TX_DESC_ADV(*tx_ring, i); tx_buffer_info = &tx_ring->tx_buffer_info[i]; + cleaned = (i == eop); skb = tx_buffer_info->skb; - if (skb) { + if (cleaned && skb) { unsigned int segs, bytecount; /* gso_segs is currently only valid for tcp */ @@ -251,23 +249,17 @@ static bool ixgbe_clean_tx_irq(struct ixgbe_adapter *adapter, ixgbe_unmap_and_free_tx_resource(adapter, tx_buffer_info); + tx_desc->wb.status = 0; + i++; if (i == tx_ring->count) i = 0; - - count++; - if (count == tx_ring->count) - goto done_cleaning; } - oldhead = head; - rmb(); - head = GET_TX_HEAD_FROM_RING(tx_ring); - head = le32_to_cpu(head); - if (head == oldhead) - goto done_cleaning; - } /* while (1) */ - -done_cleaning: + + eop = tx_ring->tx_buffer_info[i].next_to_watch; + eop_desc = IXGBE_TX_DESC_ADV(*tx_ring, eop); + } + tx_ring->next_to_clean = i; #define TX_WAKE_THRESHOLD (DESC_NEEDED * 2) @@ -301,8 +293,8 @@ done_cleaning: tx_ring->total_bytes += total_bytes; tx_ring->total_packets += total_packets; - tx_ring->stats.bytes += total_bytes; tx_ring->stats.packets += total_packets; + tx_ring->stats.bytes += total_bytes; adapter->net_stats.tx_bytes += total_bytes; adapter->net_stats.tx_packets += total_packets; return (total_packets ? true : false); @@ -1484,7 +1476,7 @@ static void ixgbe_configure_msi_and_legacy(struct ixgbe_adapter *adapter) **/ static void ixgbe_configure_tx(struct ixgbe_adapter *adapter) { - u64 tdba, tdwba; + u64 tdba; struct ixgbe_hw *hw = &adapter->hw; u32 i, j, tdlen, txctrl; @@ -1497,11 +1489,6 @@ static void ixgbe_configure_tx(struct ixgbe_adapter *adapter) IXGBE_WRITE_REG(hw, IXGBE_TDBAL(j), (tdba & DMA_32BIT_MASK)); IXGBE_WRITE_REG(hw, IXGBE_TDBAH(j), (tdba >> 32)); - tdwba = ring->dma + - (ring->count * sizeof(union ixgbe_adv_tx_desc)); - tdwba |= IXGBE_TDWBAL_HEAD_WB_ENABLE; - IXGBE_WRITE_REG(hw, IXGBE_TDWBAL(j), tdwba & DMA_32BIT_MASK); - IXGBE_WRITE_REG(hw, IXGBE_TDWBAH(j), (tdwba >> 32)); IXGBE_WRITE_REG(hw, IXGBE_TDLEN(j), tdlen); IXGBE_WRITE_REG(hw, IXGBE_TDH(j), 0); IXGBE_WRITE_REG(hw, IXGBE_TDT(j), 0); @@ -2880,8 +2867,7 @@ int ixgbe_setup_tx_resources(struct ixgbe_adapter *adapter, memset(tx_ring->tx_buffer_info, 0, size); /* round up to nearest 4K */ - tx_ring->size = tx_ring->count * sizeof(union ixgbe_adv_tx_desc) + - sizeof(u32); + tx_ring->size = tx_ring->count * sizeof(union ixgbe_adv_tx_desc); tx_ring->size = ALIGN(tx_ring->size, 4096); tx_ring->desc = pci_alloc_consistent(pdev, tx_ring->size,