Commit ea11bbe0 authored by Benjamin LaHaise's avatar Benjamin LaHaise Committed by David S. Miller
Browse files

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: default avatarBenjamin LaHaise <ben.lahaise@neterion.com>
Signed-off-by: default avatarSreenivasa Honnur <sreenivasa.honnur@neterion.com>
Signed-off-by: default avatarRamkrishna Vepa <ram.vepa@neterion.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 3f23e436

drivers/net/vxge/vxge-main.c

+5 −1
Original line number Diff line number Diff line
@@ -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...",

drivers/net/vxge/vxge-main.h

+1 −0
Original line number Diff line number Diff line
@@ -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;

};

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