vxge: prefetch skb->data

This patch implements prefetching of skb->data from a copy of the pointer
in the descriptor (which is already in the L1 cache at this point).  This
improves netperf rx performance (netperf -L 0,0 -c -H 192.168.254.2 -- -M
131072 -m 131072) by 4.9% on a P4 Xeon host.

Signed-off-by: Benjamin LaHaise <ben.lahaise@neterion.com>
Signed-off-by: Sreenivasa Honnur <sreenivasa.honnur@neterion.com>
Signed-off-by: Ramkrishna Vepa <ram.vepa@neterion.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Benjamin LaHaise 2009-08-04 10:21:57 +00:00 committed by David S. Miller
parent 3f23e436d2
commit ea11bbe0c9
2 changed files with 6 additions and 1 deletions

View File

@ -286,6 +286,7 @@ vxge_rx_alloc(void *dtrh, struct vxge_ring *ring, const int skb_size)
skb_reserve(skb, VXGE_HW_HEADER_ETHERNET_II_802_3_ALIGN);
rx_priv->skb = skb;
rx_priv->skb_data = NULL;
rx_priv->data_size = skb_size;
vxge_debug_entryexit(VXGE_TRACE,
"%s: %s:%d Exiting...", ring->ndev->name, __func__, __LINE__);
@ -305,7 +306,8 @@ static int vxge_rx_map(void *dtrh, struct vxge_ring *ring)
ring->ndev->name, __func__, __LINE__);
rx_priv = vxge_hw_ring_rxd_private_get(dtrh);
dma_addr = pci_map_single(ring->pdev, rx_priv->skb->data,
rx_priv->skb_data = rx_priv->skb->data;
dma_addr = pci_map_single(ring->pdev, rx_priv->skb_data,
rx_priv->data_size, PCI_DMA_FROMDEVICE);
if (dma_addr == 0) {
@ -450,6 +452,7 @@ vxge_rx_1b_compl(struct __vxge_hw_ring *ringh, void *dtr,
skb = rx_priv->skb;
data_size = rx_priv->data_size;
data_dma = rx_priv->data_dma;
prefetch(rx_priv->skb_data);
vxge_debug_rx(VXGE_TRACE,
"%s: %s:%d skb = 0x%p",
@ -1056,6 +1059,7 @@ vxge_rx_term(void *dtrh, enum vxge_hw_rxd_state state, void *userdata)
rx_priv->data_size, PCI_DMA_FROMDEVICE);
dev_kfree_skb(rx_priv->skb);
rx_priv->skb_data = NULL;
vxge_debug_entryexit(VXGE_TRACE,
"%s: %s:%d Exiting...",

View File

@ -378,6 +378,7 @@ struct vxgedev {
struct vxge_rx_priv {
struct sk_buff *skb;
unsigned char *skb_data;
dma_addr_t data_dma;
dma_addr_t data_size;
};