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bnx2: Add prefetches to rx path. 

Add prefetches of the skb and the next rx descriptor to speed up rx path.

Use prefetchw() for the skb [suggested by Eric Dumazet].

The rx descriptor is in skb->data which is mapped for streaming mode DMA.
Eric Dumazet pointed out that we should not prefetch the data before
dma_sync.  So we prefetch only if dma_sync is no_op on the system.

Signed-off-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Michael Chan 2010-05-06 08:58:13 +00:00 committed by David S. Miller
parent c67938a9e0
commit a33fa66bcf
2 changed files with 14 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

16
drivers/net/bnx2.c
View File

@ -2719,6 +2719,7 @@ bnx2_alloc_rx_skb(struct bnx2 *bp, struct bnx2_rx_ring_info *rxr, u16 index)
}
rx_buf->skb = skb;
rx_buf->desc = (struct l2_fhdr *) skb->data;
dma_unmap_addr_set(rx_buf, mapping, mapping);
rxbd->rx_bd_haddr_hi = (u64) mapping >> 32;
@ -2941,6 +2942,7 @@ bnx2_reuse_rx_skb(struct bnx2 *bp, struct bnx2_rx_ring_info *rxr,
rxr->rx_prod_bseq += bp->rx_buf_use_size;
prod_rx_buf->skb = skb;
prod_rx_buf->desc = (struct l2_fhdr *) skb->data;
if (cons == prod)
return;
@ -3074,6 +3076,7 @@ bnx2_rx_int(struct bnx2 *bp, struct bnx2_napi *bnapi, int budget)
u16 hw_cons, sw_cons, sw_ring_cons, sw_prod, sw_ring_prod;
struct l2_fhdr *rx_hdr;
int rx_pkt = 0, pg_ring_used = 0;
struct pci_dev *pdev = bp->pdev;
hw_cons = bnx2_get_hw_rx_cons(bnapi);
sw_cons = rxr->rx_cons;
@ -3086,7 +3089,7 @@ bnx2_rx_int(struct bnx2 *bp, struct bnx2_napi *bnapi, int budget)
while (sw_cons != hw_cons) {
unsigned int len, hdr_len;
u32 status;
struct sw_bd *rx_buf;
struct sw_bd *rx_buf, *next_rx_buf;
struct sk_buff *skb;
dma_addr_t dma_addr;
u16 vtag = 0;
@ -3097,7 +3100,14 @@ bnx2_rx_int(struct bnx2 *bp, struct bnx2_napi *bnapi, int budget)
rx_buf = &rxr->rx_buf_ring[sw_ring_cons];
skb = rx_buf->skb;
prefetchw(skb);
if (!get_dma_ops(&pdev->dev)->sync_single_for_cpu) {
next_rx_buf =
&rxr->rx_buf_ring[
RX_RING_IDX(NEXT_RX_BD(sw_cons))];
prefetch(next_rx_buf->desc);
}
rx_buf->skb = NULL;
dma_addr = dma_unmap_addr(rx_buf, mapping);
@ -3106,7 +3116,7 @@ bnx2_rx_int(struct bnx2 *bp, struct bnx2_napi *bnapi, int budget)
BNX2_RX_OFFSET + BNX2_RX_COPY_THRESH,
PCI_DMA_FROMDEVICE);
rx_hdr = (struct l2_fhdr *) skb->data;
rx_hdr = rx_buf->desc;
len = rx_hdr->l2_fhdr_pkt_len;
status = rx_hdr->l2_fhdr_status;
@ -5764,7 +5774,7 @@ bnx2_run_loopback(struct bnx2 *bp, int loopback_mode)
rx_buf = &rxr->rx_buf_ring[rx_start_idx];
rx_skb = rx_buf->skb;
rx_hdr = (struct l2_fhdr *) rx_skb->data;
rx_hdr = rx_buf->desc;
skb_reserve(rx_skb, BNX2_RX_OFFSET);
pci_dma_sync_single_for_cpu(bp->pdev,

1
drivers/net/bnx2.h
View File

@ -6551,6 +6551,7 @@ struct l2_fhdr {
struct sw_bd {
struct sk_buff *skb;
struct l2_fhdr *desc;
DEFINE_DMA_UNMAP_ADDR(mapping);
};