[NET] Fix PCnet32 performance bug on non-coherent architecutres
From: Ralf Baechle <hidden>
Date: 2007-03-04 22:32:27
Subsystem:
networking drivers, the rest · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
The PCnet32 driver always passed the the size of the largest possible packet to the pci_dma_sync_single_for_cpu and pci_dma_sync_single_for_device. This results in a fairly large "colateral damage" in the caches and makes the flush operation itself much slower. On a system with a 40MHz CPU this patch increases network bandwidth by about 12%. Signed-off-by: Ralf Baechle <redacted>
diff --git a/drivers/net/pcnet32.c b/drivers/net/pcnet32.c
index 36f9d98..4d94ba7 100644
--- a/drivers/net/pcnet32.c
+++ b/drivers/net/pcnet32.c@@ -1234,14 +1234,14 @@ static void pcnet32_rx_entry(struct net_device *dev, skb_put(skb, pkt_len); /* Make room */ pci_dma_sync_single_for_cpu(lp->pci_dev, lp->rx_dma_addr[entry], - PKT_BUF_SZ - 2, + pkt_len, PCI_DMA_FROMDEVICE); eth_copy_and_sum(skb, (unsigned char *)(lp->rx_skbuff[entry]->data), pkt_len, 0); pci_dma_sync_single_for_device(lp->pci_dev, lp->rx_dma_addr[entry], - PKT_BUF_SZ - 2, + pkt_len, PCI_DMA_FROMDEVICE); } lp->stats.rx_bytes += skb->len;