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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>
This commit is contained in:
Nick Nunley 2010-05-04 21:58:07 +00:00 committed by David S. Miller
parent a84afa40e0
commit 2873957df0
2 changed files with 22 additions and 27 deletions
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4
drivers/net/igb/igb.h
View File

@ -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 {

45
drivers/net/igb/igb_main.c
View File

@ -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);