From 0e014cb16234c3797aa518d46fe7e1fe91ebcca9 Mon Sep 17 00:00:00 2001 From: Alexander Duyck Date: Fri, 26 Dec 2008 01:33:18 -0800 Subject: [PATCH] igb: defeature tx head writeback This patch removes tx head writeback as it was found to not provide a significant improvement in tx performance and on some systems has been seen to cause a performance degredation due to partial cache line writes. Signed-off-by: Alexander Duyck Signed-off-by: Jeff Kirsher Signed-off-by: David S. Miller --- drivers/net/igb/e1000_defines.h | 1 + drivers/net/igb/igb.h | 5 +- drivers/net/igb/igb_main.c | 85 ++++++++++++++------------------- 3 files changed, 39 insertions(+), 52 deletions(-) diff --git a/drivers/net/igb/e1000_defines.h b/drivers/net/igb/e1000_defines.h index c5fe784c9e3..40d03426c12 100644 --- a/drivers/net/igb/e1000_defines.h +++ b/drivers/net/igb/e1000_defines.h @@ -323,6 +323,7 @@ #define E1000_TXD_CMD_IFCS 0x02000000 /* Insert FCS (Ethernet CRC) */ #define E1000_TXD_CMD_RS 0x08000000 /* Report Status */ #define E1000_TXD_CMD_DEXT 0x20000000 /* Descriptor extension (0 = legacy) */ +#define E1000_TXD_STAT_DD 0x00000001 /* Descriptor Done */ /* Extended desc bits for Linksec and timesync */ /* Transmit Control */ diff --git a/drivers/net/igb/igb.h b/drivers/net/igb/igb.h index 2121b8bc6ea..c90632524fd 100644 --- a/drivers/net/igb/igb.h +++ b/drivers/net/igb/igb.h @@ -43,8 +43,6 @@ struct igb_adapter; #endif /* Interrupt defines */ -#define IGB_MAX_TX_CLEAN 72 - #define IGB_MIN_DYN_ITR 3000 #define IGB_MAX_DYN_ITR 96000 @@ -127,7 +125,8 @@ struct igb_buffer { /* TX */ struct { unsigned long time_stamp; - u32 length; + u16 length; + u16 next_to_watch; }; /* RX */ struct { diff --git a/drivers/net/igb/igb_main.c b/drivers/net/igb/igb_main.c index 6a40d9486da..4962cdfc507 100644 --- a/drivers/net/igb/igb_main.c +++ b/drivers/net/igb/igb_main.c @@ -1575,8 +1575,7 @@ int igb_setup_tx_resources(struct igb_adapter *adapter, memset(tx_ring->buffer_info, 0, size); /* round up to nearest 4K */ - tx_ring->size = tx_ring->count * sizeof(struct e1000_tx_desc) - + sizeof(u32); + tx_ring->size = tx_ring->count * sizeof(struct e1000_tx_desc); tx_ring->size = ALIGN(tx_ring->size, 4096); tx_ring->desc = pci_alloc_consistent(pdev, tx_ring->size, @@ -1635,7 +1634,7 @@ static int igb_setup_all_tx_resources(struct igb_adapter *adapter) **/ static void igb_configure_tx(struct igb_adapter *adapter) { - u64 tdba, tdwba; + u64 tdba; struct e1000_hw *hw = &adapter->hw; u32 tctl; u32 txdctl, txctrl; @@ -1651,12 +1650,6 @@ static void igb_configure_tx(struct igb_adapter *adapter) tdba & 0x00000000ffffffffULL); wr32(E1000_TDBAH(i), tdba >> 32); - tdwba = ring->dma + ring->count * sizeof(struct e1000_tx_desc); - tdwba |= 1; /* enable head wb */ - wr32(E1000_TDWBAL(i), - tdwba & 0x00000000ffffffffULL); - wr32(E1000_TDWBAH(i), tdwba >> 32); - ring->head = E1000_TDH(i); ring->tail = E1000_TDT(i); writel(0, hw->hw_addr + ring->tail); @@ -2710,6 +2703,7 @@ static inline int igb_tso_adv(struct igb_adapter *adapter, context_desc->seqnum_seed = 0; buffer_info->time_stamp = jiffies; + buffer_info->next_to_watch = i; buffer_info->dma = 0; i++; if (i == tx_ring->count) @@ -2773,6 +2767,7 @@ static inline bool igb_tx_csum_adv(struct igb_adapter *adapter, cpu_to_le32(tx_ring->queue_index << 4); buffer_info->time_stamp = jiffies; + buffer_info->next_to_watch = i; buffer_info->dma = 0; i++; @@ -2791,8 +2786,8 @@ static inline bool igb_tx_csum_adv(struct igb_adapter *adapter, #define IGB_MAX_DATA_PER_TXD (1<length = len; /* set time_stamp *before* dma to help avoid a possible race */ buffer_info->time_stamp = jiffies; + buffer_info->next_to_watch = i; buffer_info->dma = pci_map_single(adapter->pdev, skb->data, len, PCI_DMA_TODEVICE); count++; @@ -2823,6 +2819,7 @@ static inline int igb_tx_map_adv(struct igb_adapter *adapter, BUG_ON(len >= IGB_MAX_DATA_PER_TXD); buffer_info->length = len; buffer_info->time_stamp = jiffies; + buffer_info->next_to_watch = i; buffer_info->dma = pci_map_page(adapter->pdev, frag->page, frag->page_offset, @@ -2835,8 +2832,9 @@ static inline int igb_tx_map_adv(struct igb_adapter *adapter, i = 0; } - i = (i == 0) ? tx_ring->count - 1 : i - 1; + i = ((i == 0) ? tx_ring->count - 1 : i - 1); tx_ring->buffer_info[i].skb = skb; + tx_ring->buffer_info[first].next_to_watch = i; return count; } @@ -2943,6 +2941,7 @@ static int igb_xmit_frame_ring_adv(struct sk_buff *skb, struct igb_ring *tx_ring) { struct igb_adapter *adapter = netdev_priv(netdev); + unsigned int first; unsigned int tx_flags = 0; unsigned int len; u8 hdr_len = 0; @@ -2979,6 +2978,8 @@ static int igb_xmit_frame_ring_adv(struct sk_buff *skb, if (skb->protocol == htons(ETH_P_IP)) tx_flags |= IGB_TX_FLAGS_IPV4; + first = tx_ring->next_to_use; + tso = skb_is_gso(skb) ? igb_tso_adv(adapter, tx_ring, skb, tx_flags, &hdr_len) : 0; @@ -2994,7 +2995,7 @@ static int igb_xmit_frame_ring_adv(struct sk_buff *skb, tx_flags |= IGB_TX_FLAGS_CSUM; igb_tx_queue_adv(adapter, tx_ring, tx_flags, - igb_tx_map_adv(adapter, tx_ring, skb), + igb_tx_map_adv(adapter, tx_ring, skb, first), skb->len, hdr_len); netdev->trans_start = jiffies; @@ -3617,12 +3618,6 @@ static int igb_clean_rx_ring_msix(struct napi_struct *napi, int budget) return 1; } -static inline u32 get_head(struct igb_ring *tx_ring) -{ - void *end = (struct e1000_tx_desc *)tx_ring->desc + tx_ring->count; - return le32_to_cpu(*(volatile __le32 *)end); -} - /** * igb_clean_tx_irq - Reclaim resources after transmit completes * @adapter: board private structure @@ -3631,24 +3626,25 @@ static inline u32 get_head(struct igb_ring *tx_ring) static bool igb_clean_tx_irq(struct igb_ring *tx_ring) { struct igb_adapter *adapter = tx_ring->adapter; - struct e1000_hw *hw = &adapter->hw; struct net_device *netdev = adapter->netdev; - struct e1000_tx_desc *tx_desc; + struct e1000_hw *hw = &adapter->hw; struct igb_buffer *buffer_info; struct sk_buff *skb; - unsigned int i; - u32 head, oldhead; - unsigned int count = 0; + union e1000_adv_tx_desc *tx_desc, *eop_desc; unsigned int total_bytes = 0, total_packets = 0; - bool retval = true; + unsigned int i, eop, count = 0; + bool cleaned = false; - rmb(); - head = get_head(tx_ring); i = tx_ring->next_to_clean; - while (1) { - while (i != head) { - tx_desc = E1000_TX_DESC(*tx_ring, i); + eop = tx_ring->buffer_info[i].next_to_watch; + eop_desc = E1000_TX_DESC_ADV(*tx_ring, eop); + + while ((eop_desc->wb.status & cpu_to_le32(E1000_TXD_STAT_DD)) && + (count < tx_ring->count)) { + for (cleaned = false; !cleaned; count++) { + tx_desc = E1000_TX_DESC_ADV(*tx_ring, i); buffer_info = &tx_ring->buffer_info[i]; + cleaned = (i == eop); skb = buffer_info->skb; if (skb) { @@ -3663,25 +3659,17 @@ static bool igb_clean_tx_irq(struct igb_ring *tx_ring) } igb_unmap_and_free_tx_resource(adapter, buffer_info); + tx_desc->wb.status = 0; i++; if (i == tx_ring->count) i = 0; - - count++; - if (count == IGB_MAX_TX_CLEAN) { - retval = false; - goto done_cleaning; - } } - oldhead = head; - rmb(); - head = get_head(tx_ring); - if (head == oldhead) - goto done_cleaning; - } /* while (1) */ - -done_cleaning: + + eop = tx_ring->buffer_info[i].next_to_watch; + eop_desc = E1000_TX_DESC_ADV(*tx_ring, eop); + } + tx_ring->next_to_clean = i; if (unlikely(count && @@ -3708,7 +3696,6 @@ done_cleaning: && !(rd32(E1000_STATUS) & E1000_STATUS_TXOFF)) { - tx_desc = E1000_TX_DESC(*tx_ring, i); /* detected Tx unit hang */ dev_err(&adapter->pdev->dev, "Detected Tx Unit Hang\n" @@ -3717,9 +3704,9 @@ done_cleaning: " TDT <%x>\n" " next_to_use <%x>\n" " next_to_clean <%x>\n" - " head (WB) <%x>\n" "buffer_info[next_to_clean]\n" " time_stamp <%lx>\n" + " next_to_watch <%x>\n" " jiffies <%lx>\n" " desc.status <%x>\n", tx_ring->queue_index, @@ -3727,10 +3714,10 @@ done_cleaning: readl(adapter->hw.hw_addr + tx_ring->tail), tx_ring->next_to_use, tx_ring->next_to_clean, - head, tx_ring->buffer_info[i].time_stamp, + eop, jiffies, - tx_desc->upper.fields.status); + eop_desc->wb.status); netif_stop_subqueue(netdev, tx_ring->queue_index); } } @@ -3740,7 +3727,7 @@ done_cleaning: tx_ring->tx_stats.packets += total_packets; adapter->net_stats.tx_bytes += total_bytes; adapter->net_stats.tx_packets += total_packets; - return retval; + return (count < tx_ring->count); } #ifdef CONFIG_IGB_LRO -- 2.41.1