From 2873957df0ead5b53fa00fddfb52ca3df38af4a9 Mon Sep 17 00:00:00 2001 From: Nick Nunley Date: Tue, 4 May 2010 21:58:07 +0000 Subject: [PATCH] igb: reduce cache misses on tx cleanup This patch reduces the number of skb cache misses in the clean_tx_irq path, and results in an overall increase in tx packet throughput. Signed-off-by: Nicholas Nunley Signed-off-by: Jeff Kirsher Signed-off-by: David S. Miller --- drivers/net/igb/igb.h | 4 +++- drivers/net/igb/igb_main.c | 45 +++++++++++++++++++-------------------------- 2 files changed, 22 insertions(+), 27 deletions(-) diff --git a/drivers/net/igb/igb.h b/drivers/net/igb/igb.h index 735ede9..6e63d9a 100644 --- a/drivers/net/igb/igb.h +++ b/drivers/net/igb/igb.h @@ -141,8 +141,10 @@ struct igb_buffer { unsigned long time_stamp; u16 length; u16 next_to_watch; - u16 mapped_as_page; + unsigned int bytecount; u16 gso_segs; + union skb_shared_tx shtx; + u8 mapped_as_page; }; /* RX */ struct { diff --git a/drivers/net/igb/igb_main.c b/drivers/net/igb/igb_main.c index 438737d..589cf4a 100644 --- a/drivers/net/igb/igb_main.c +++ b/drivers/net/igb/igb_main.c @@ -3899,34 +3899,33 @@ static inline int igb_tx_map_adv(struct igb_ring *tx_ring, struct sk_buff *skb, { struct igb_buffer *buffer_info; struct device *dev = tx_ring->dev; - unsigned int len = skb_headlen(skb); + unsigned int hlen = skb_headlen(skb); unsigned int count = 0, i; unsigned int f; + u16 gso_segs = skb_shinfo(skb)->gso_segs ?: 1; i = tx_ring->next_to_use; buffer_info = &tx_ring->buffer_info[i]; - BUG_ON(len >= IGB_MAX_DATA_PER_TXD); - buffer_info->length = len; + BUG_ON(hlen >= IGB_MAX_DATA_PER_TXD); + buffer_info->length = hlen; /* 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 = dma_map_single(dev, skb->data, len, + buffer_info->dma = dma_map_single(dev, skb->data, hlen, DMA_TO_DEVICE); if (dma_mapping_error(dev, buffer_info->dma)) goto dma_error; for (f = 0; f < skb_shinfo(skb)->nr_frags; f++) { - struct skb_frag_struct *frag; + struct skb_frag_struct *frag = &skb_shinfo(skb)->frags[f]; + unsigned int len = frag->size; count++; i++; if (i == tx_ring->count) i = 0; - frag = &skb_shinfo(skb)->frags[f]; - len = frag->size; - buffer_info = &tx_ring->buffer_info[i]; BUG_ON(len >= IGB_MAX_DATA_PER_TXD); buffer_info->length = len; @@ -3944,7 +3943,10 @@ static inline int igb_tx_map_adv(struct igb_ring *tx_ring, struct sk_buff *skb, } tx_ring->buffer_info[i].skb = skb; - tx_ring->buffer_info[i].gso_segs = skb_shinfo(skb)->gso_segs ?: 1; + tx_ring->buffer_info[i].shtx = skb_shinfo(skb)->tx_flags; + /* multiply data chunks by size of headers */ + tx_ring->buffer_info[i].bytecount = ((gso_segs - 1) * hlen) + skb->len; + tx_ring->buffer_info[i].gso_segs = gso_segs; tx_ring->buffer_info[first].next_to_watch = i; return ++count; @@ -5288,22 +5290,21 @@ static void igb_systim_to_hwtstamp(struct igb_adapter *adapter, /** * igb_tx_hwtstamp - utility function which checks for TX time stamp * @q_vector: pointer to q_vector containing needed info - * @skb: packet that was just sent + * @buffer: pointer to igb_buffer structure * * If we were asked to do hardware stamping and such a time stamp is * available, then it must have been for this skb here because we only * allow only one such packet into the queue. */ -static void igb_tx_hwtstamp(struct igb_q_vector *q_vector, struct sk_buff *skb) +static void igb_tx_hwtstamp(struct igb_q_vector *q_vector, struct igb_buffer *buffer_info) { struct igb_adapter *adapter = q_vector->adapter; - union skb_shared_tx *shtx = skb_tx(skb); struct e1000_hw *hw = &adapter->hw; struct skb_shared_hwtstamps shhwtstamps; u64 regval; /* if skb does not support hw timestamp or TX stamp not valid exit */ - if (likely(!shtx->hardware) || + if (likely(!buffer_info->shtx.hardware) || !(rd32(E1000_TSYNCTXCTL) & E1000_TSYNCTXCTL_VALID)) return; @@ -5311,7 +5312,7 @@ static void igb_tx_hwtstamp(struct igb_q_vector *q_vector, struct sk_buff *skb) regval |= (u64)rd32(E1000_TXSTMPH) << 32; igb_systim_to_hwtstamp(adapter, &shhwtstamps, regval); - skb_tstamp_tx(skb, &shhwtstamps); + skb_tstamp_tx(buffer_info->skb, &shhwtstamps); } /** @@ -5326,7 +5327,6 @@ static bool igb_clean_tx_irq(struct igb_q_vector *q_vector) struct net_device *netdev = tx_ring->netdev; struct e1000_hw *hw = &adapter->hw; struct igb_buffer *buffer_info; - struct sk_buff *skb; union e1000_adv_tx_desc *tx_desc, *eop_desc; unsigned int total_bytes = 0, total_packets = 0; unsigned int i, eop, count = 0; @@ -5342,19 +5342,12 @@ static bool igb_clean_tx_irq(struct igb_q_vector *q_vector) 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) { - unsigned int segs, bytecount; + if (buffer_info->skb) { + total_bytes += buffer_info->bytecount; /* gso_segs is currently only valid for tcp */ - segs = buffer_info->gso_segs; - /* multiply data chunks by size of headers */ - bytecount = ((segs - 1) * skb_headlen(skb)) + - skb->len; - total_packets += segs; - total_bytes += bytecount; - - igb_tx_hwtstamp(q_vector, skb); + total_packets += buffer_info->gso_segs; + igb_tx_hwtstamp(q_vector, buffer_info); } igb_unmap_and_free_tx_resource(tx_ring, buffer_info); -- 2.7.4