From e01c31a5f7eb4f8a147cf6205f0f2ef11146068d Mon Sep 17 00:00:00 2001 From: Jesse Brandeburg Date: Tue, 26 Aug 2008 04:27:13 -0700 Subject: [PATCH] ixgbe: Implement Tx Head Writeback Enable Tx Head Writeback in the hardware. This helps performance by removing adapter writebacks to descriptors on transmit completion. Signed-off-by: Jesse Brandeburg Signed-off-by: Peter P Waskiewicz Jr Signed-off-by: Jeff Kirsher Signed-off-by: Jeff Garzik --- drivers/net/ixgbe/ixgbe_main.c | 198 +++++++++++++++++++++++------------------ 1 file changed, 113 insertions(+), 85 deletions(-) diff --git a/drivers/net/ixgbe/ixgbe_main.c b/drivers/net/ixgbe/ixgbe_main.c index cba7a38..95d0041 100644 --- a/drivers/net/ixgbe/ixgbe_main.c +++ b/drivers/net/ixgbe/ixgbe_main.c @@ -148,8 +148,7 @@ static void ixgbe_unmap_and_free_tx_resource(struct ixgbe_adapter *adapter, *tx_buffer_info) { if (tx_buffer_info->dma) { - pci_unmap_page(adapter->pdev, - tx_buffer_info->dma, + pci_unmap_page(adapter->pdev, tx_buffer_info->dma, tx_buffer_info->length, PCI_DMA_TODEVICE); tx_buffer_info->dma = 0; } @@ -162,32 +161,35 @@ static void ixgbe_unmap_and_free_tx_resource(struct ixgbe_adapter *adapter, static inline bool ixgbe_check_tx_hang(struct ixgbe_adapter *adapter, struct ixgbe_ring *tx_ring, - unsigned int eop, - union ixgbe_adv_tx_desc *eop_desc) + unsigned int eop) { + struct ixgbe_hw *hw = &adapter->hw; + u32 head, tail; + /* Detect a transmit hang in hardware, this serializes the - * check with the clearing of time_stamp and movement of i */ + * check with the clearing of time_stamp and movement of eop */ + head = IXGBE_READ_REG(hw, tx_ring->head); + tail = IXGBE_READ_REG(hw, tx_ring->tail); adapter->detect_tx_hung = false; - if (tx_ring->tx_buffer_info[eop].dma && + if ((head != tail) && + tx_ring->tx_buffer_info[eop].time_stamp && time_after(jiffies, tx_ring->tx_buffer_info[eop].time_stamp + HZ) && !(IXGBE_READ_REG(&adapter->hw, IXGBE_TFCS) & IXGBE_TFCS_TXOFF)) { /* detected Tx unit hang */ + union ixgbe_adv_tx_desc *tx_desc; + tx_desc = IXGBE_TX_DESC_ADV(*tx_ring, eop); DPRINTK(DRV, ERR, "Detected Tx Unit Hang\n" - " TDH <%x>\n" - " TDT <%x>\n" + " Tx Queue <%d>\n" + " TDH, TDT <%x>, <%x>\n" " next_to_use <%x>\n" " next_to_clean <%x>\n" "tx_buffer_info[next_to_clean]\n" " time_stamp <%lx>\n" - " next_to_watch <%x>\n" - " jiffies <%lx>\n" - " next_to_watch.status <%x>\n", - readl(adapter->hw.hw_addr + tx_ring->head), - readl(adapter->hw.hw_addr + tx_ring->tail), - tx_ring->next_to_use, - tx_ring->next_to_clean, - tx_ring->tx_buffer_info[eop].time_stamp, - eop, jiffies, eop_desc->wb.status); + " jiffies <%lx>\n", + tx_ring->queue_index, + head, tail, + tx_ring->next_to_use, eop, + tx_ring->tx_buffer_info[eop].time_stamp, jiffies); return true; } @@ -203,65 +205,75 @@ 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); + /** * ixgbe_clean_tx_irq - Reclaim resources after transmit completes * @adapter: board private structure + * @tx_ring: tx ring to clean **/ static bool ixgbe_clean_tx_irq(struct ixgbe_adapter *adapter, - struct ixgbe_ring *tx_ring) + struct ixgbe_ring *tx_ring) { - struct net_device *netdev = adapter->netdev; - union ixgbe_adv_tx_desc *tx_desc, *eop_desc; + union ixgbe_adv_tx_desc *tx_desc; struct ixgbe_tx_buffer *tx_buffer_info; - unsigned int i, eop; - bool cleaned = false; - unsigned int total_tx_bytes = 0, total_tx_packets = 0; + struct net_device *netdev = adapter->netdev; + struct sk_buff *skb; + unsigned int i; + u32 head, oldhead; + unsigned int 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; - 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)) { - cleaned = false; - while (!cleaned) { + while (1) { + while (i != head) { 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; - tx_ring->stats.bytes += tx_buffer_info->length; - if (cleaned) { - struct sk_buff *skb = tx_buffer_info->skb; + if (skb) { unsigned int segs, bytecount; + + /* gso_segs is currently only valid for tcp */ segs = skb_shinfo(skb)->gso_segs ?: 1; /* multiply data chunks by size of headers */ bytecount = ((segs - 1) * skb_headlen(skb)) + - skb->len; - total_tx_packets += segs; - total_tx_bytes += bytecount; + skb->len; + total_packets += segs; + total_bytes += bytecount; } + ixgbe_unmap_and_free_tx_resource(adapter, - tx_buffer_info); - tx_desc->wb.status = 0; + tx_buffer_info); i++; if (i == tx_ring->count) i = 0; - } - - tx_ring->stats.packets++; - - eop = tx_ring->tx_buffer_info[i].next_to_watch; - eop_desc = IXGBE_TX_DESC_ADV(*tx_ring, eop); - - /* weight of a sort for tx, avoid endless transmit cleanup */ - if (total_tx_packets >= tx_ring->work_limit) - break; - } + 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: tx_ring->next_to_clean = i; #define TX_WAKE_THRESHOLD (DESC_NEEDED * 2) - if (total_tx_packets && netif_carrier_ok(netdev) && - (IXGBE_DESC_UNUSED(tx_ring) >= TX_WAKE_THRESHOLD)) { + if (unlikely(count && netif_carrier_ok(netdev) && + (IXGBE_DESC_UNUSED(tx_ring) >= TX_WAKE_THRESHOLD))) { /* Make sure that anybody stopping the queue after this * sees the new next_to_clean. */ @@ -269,23 +281,32 @@ static bool ixgbe_clean_tx_irq(struct ixgbe_adapter *adapter, if (__netif_subqueue_stopped(netdev, tx_ring->queue_index) && !test_bit(__IXGBE_DOWN, &adapter->state)) { netif_wake_subqueue(netdev, tx_ring->queue_index); - adapter->restart_queue++; + ++adapter->restart_queue; } } - if (adapter->detect_tx_hung) - if (ixgbe_check_tx_hang(adapter, tx_ring, eop, eop_desc)) - netif_stop_subqueue(netdev, tx_ring->queue_index); + if (adapter->detect_tx_hung) { + if (ixgbe_check_tx_hang(adapter, tx_ring, i)) { + /* schedule immediate reset if we believe we hung */ + DPRINTK(PROBE, INFO, + "tx hang %d detected, resetting adapter\n", + adapter->tx_timeout_count + 1); + ixgbe_tx_timeout(adapter->netdev); + } + } - if (total_tx_packets >= tx_ring->work_limit) - IXGBE_WRITE_REG(&adapter->hw, IXGBE_EICS, tx_ring->eims_value); + /* re-arm the interrupt */ + if ((total_packets >= tx_ring->work_limit) || + (count == tx_ring->count)) + IXGBE_WRITE_REG(&adapter->hw, IXGBE_EICS, tx_ring->v_idx); - tx_ring->total_bytes += total_tx_bytes; - tx_ring->total_packets += total_tx_packets; - adapter->net_stats.tx_bytes += total_tx_bytes; - adapter->net_stats.tx_packets += total_tx_packets; - cleaned = total_tx_packets ? true : false; - return cleaned; + tx_ring->total_bytes += total_bytes; + tx_ring->total_packets += total_packets; + tx_ring->stats.bytes += total_bytes; + tx_ring->stats.packets += total_packets; + adapter->net_stats.tx_bytes += total_bytes; + adapter->net_stats.tx_packets += total_packets; + return (total_packets ? true : false); } #ifdef CONFIG_DCA @@ -1344,19 +1365,24 @@ static void ixgbe_configure_msi_and_legacy(struct ixgbe_adapter *adapter) **/ static void ixgbe_configure_tx(struct ixgbe_adapter *adapter) { - u64 tdba; + u64 tdba, tdwba; struct ixgbe_hw *hw = &adapter->hw; u32 i, j, tdlen, txctrl; /* Setup the HW Tx Head and Tail descriptor pointers */ for (i = 0; i < adapter->num_tx_queues; i++) { - j = adapter->tx_ring[i].reg_idx; - tdba = adapter->tx_ring[i].dma; - tdlen = adapter->tx_ring[i].count * - sizeof(union ixgbe_adv_tx_desc); + struct ixgbe_ring *ring = &adapter->tx_ring[i]; + j = ring->reg_idx; + tdba = ring->dma; + tdlen = ring->count * sizeof(union ixgbe_adv_tx_desc); IXGBE_WRITE_REG(hw, IXGBE_TDBAL(j), - (tdba & DMA_32BIT_MASK)); + (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); @@ -1365,9 +1391,9 @@ static void ixgbe_configure_tx(struct ixgbe_adapter *adapter) /* Disable Tx Head Writeback RO bit, since this hoses * bookkeeping if things aren't delivered in order. */ - txctrl = IXGBE_READ_REG(hw, IXGBE_DCA_TXCTRL(i)); + txctrl = IXGBE_READ_REG(hw, IXGBE_DCA_TXCTRL(j)); txctrl &= ~IXGBE_DCA_TXCTRL_TX_WB_RO_EN; - IXGBE_WRITE_REG(hw, IXGBE_DCA_TXCTRL(i), txctrl); + IXGBE_WRITE_REG(hw, IXGBE_DCA_TXCTRL(j), txctrl); } } @@ -1775,6 +1801,8 @@ static int ixgbe_up_complete(struct ixgbe_adapter *adapter) for (i = 0; i < adapter->num_tx_queues; i++) { j = adapter->tx_ring[i].reg_idx; txdctl = IXGBE_READ_REG(hw, IXGBE_TXDCTL(j)); + /* enable WTHRESH=8 descriptors, to encourage burst writeback */ + txdctl |= (8 << 16); txdctl |= IXGBE_TXDCTL_ENABLE; IXGBE_WRITE_REG(hw, IXGBE_TXDCTL(j), txdctl); } @@ -2487,38 +2515,38 @@ static int __devinit ixgbe_sw_init(struct ixgbe_adapter *adapter) * Return 0 on success, negative on failure **/ int ixgbe_setup_tx_resources(struct ixgbe_adapter *adapter, - struct ixgbe_ring *tx_ring) + struct ixgbe_ring *tx_ring) { struct pci_dev *pdev = adapter->pdev; int size; size = sizeof(struct ixgbe_tx_buffer) * tx_ring->count; tx_ring->tx_buffer_info = vmalloc(size); - if (!tx_ring->tx_buffer_info) { - DPRINTK(PROBE, ERR, - "Unable to allocate memory for the transmit descriptor ring\n"); - return -ENOMEM; - } + if (!tx_ring->tx_buffer_info) + goto err; 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); + tx_ring->size = tx_ring->count * sizeof(union ixgbe_adv_tx_desc) + + sizeof(u32); tx_ring->size = ALIGN(tx_ring->size, 4096); tx_ring->desc = pci_alloc_consistent(pdev, tx_ring->size, &tx_ring->dma); - if (!tx_ring->desc) { - vfree(tx_ring->tx_buffer_info); - DPRINTK(PROBE, ERR, - "Memory allocation failed for the tx desc ring\n"); - return -ENOMEM; - } + if (!tx_ring->desc) + goto err; tx_ring->next_to_use = 0; tx_ring->next_to_clean = 0; tx_ring->work_limit = tx_ring->count; - return 0; + +err: + vfree(tx_ring->tx_buffer_info); + tx_ring->tx_buffer_info = NULL; + DPRINTK(PROBE, ERR, "Unable to allocate memory for the transmit " + "descriptor ring\n"); + return -ENOMEM; } /** @@ -2581,7 +2609,7 @@ alloc_failed: * Free all transmit software resources **/ static void ixgbe_free_tx_resources(struct ixgbe_adapter *adapter, - struct ixgbe_ring *tx_ring) + struct ixgbe_ring *tx_ring) { struct pci_dev *pdev = adapter->pdev; -- 2.7.4