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authorNick Nunley2010-05-04 21:58:07 +0000
committerDavid S. Miller2010-05-05 21:30:12 -0700
commit2873957df0ead5b53fa00fddfb52ca3df38af4a9 (patch)
tree3332fef2c0b6ac1877299ab171ce7a316a786301 /drivers
parenta84afa40e07b6882ca46a7287d8ca4a8c5430f60 (diff)
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 <nicholasx.d.nunley@intel.com> Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/net/igb/igb.h4
-rw-r--r--drivers/net/igb/igb_main.c45
2 files changed, 22 insertions, 27 deletions
diff --git a/drivers/net/igb/igb.h b/drivers/net/igb/igb.h
index 735ede9c7d75..6e63d9a7fc75 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 438737d58688..589cf4a6427a 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);