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enic: implement rx_copybreak

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Calling dma_map_single()/dma_unmap_single() is quite expensive compared
to copying a small packet. So let's copy short frames and keep the buffers
mapped.

Signed-off-by: Govindarajulu Varadarajan <_govind@gmx.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Govindarajulu Varadarajan 2014-09-03 03:17:19 +05:30 committed by David S. Miller
parent e020836d95
commit a03bb56e67
2 changed files with 48 additions and 3 deletions
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1
drivers/net/ethernet/cisco/enic/enic.h
View File

@ -186,6 +186,7 @@ struct enic {
____cacheline_aligned struct vnic_cq cq[ENIC_CQ_MAX];
unsigned int cq_count;
struct enic_rfs_flw_tbl rfs_h;
u32 rx_copybreak;
};
static inline struct device *enic_get_dev(struct enic *enic)

50
drivers/net/ethernet/cisco/enic/enic_main.c
View File

@ -66,6 +66,8 @@
#define PCI_DEVICE_ID_CISCO_VIC_ENET_DYN 0x0044 /* enet dynamic vnic */
#define PCI_DEVICE_ID_CISCO_VIC_ENET_VF 0x0071 /* enet SRIOV VF */
#define RX_COPYBREAK_DEFAULT 256
/* Supported devices */
static const struct pci_device_id enic_id_table[] = {
{ PCI_VDEVICE(CISCO, PCI_DEVICE_ID_CISCO_VIC_ENET) },
@ -924,6 +926,7 @@ static void enic_free_rq_buf(struct vnic_rq *rq, struct vnic_rq_buf *buf)
pci_unmap_single(enic->pdev, buf->dma_addr,
buf->len, PCI_DMA_FROMDEVICE);
dev_kfree_skb_any(buf->os_buf);
buf->os_buf = NULL;
}
static int enic_rq_alloc_buf(struct vnic_rq *rq)
@ -934,7 +937,24 @@ static int enic_rq_alloc_buf(struct vnic_rq *rq)
unsigned int len = netdev->mtu + VLAN_ETH_HLEN;
unsigned int os_buf_index = 0;
dma_addr_t dma_addr;
struct vnic_rq_buf *buf = rq->to_use;
if (buf->os_buf) {
buf = buf->next;
rq->to_use = buf;
rq->ring.desc_avail--;
if ((buf->index & VNIC_RQ_RETURN_RATE) == 0) {
/* Adding write memory barrier prevents compiler and/or
* CPU reordering, thus avoiding descriptor posting
* before descriptor is initialized. Otherwise, hardware
* can read stale descriptor fields.
*/
wmb();
iowrite32(buf->index, &rq->ctrl->posted_index);
}
return 0;
}
skb = netdev_alloc_skb_ip_align(netdev, len);
if (!skb)
return -ENOMEM;
@ -957,6 +977,25 @@ static void enic_intr_update_pkt_size(struct vnic_rx_bytes_counter *pkt_size,
pkt_size->small_pkt_bytes_cnt += pkt_len;
}
static bool enic_rxcopybreak(struct net_device *netdev, struct sk_buff **skb,
struct vnic_rq_buf *buf, u16 len)
{
struct enic *enic = netdev_priv(netdev);
struct sk_buff *new_skb;
if (len > enic->rx_copybreak)
return false;
new_skb = netdev_alloc_skb_ip_align(netdev, len);
if (!new_skb)
return false;
pci_dma_sync_single_for_cpu(enic->pdev, buf->dma_addr, len,
DMA_FROM_DEVICE);
memcpy(new_skb->data, (*skb)->data, len);
*skb = new_skb;
return true;
}
static void enic_rq_indicate_buf(struct vnic_rq *rq,
struct cq_desc *cq_desc, struct vnic_rq_buf *buf,
int skipped, void *opaque)
@ -978,9 +1017,6 @@ static void enic_rq_indicate_buf(struct vnic_rq *rq,
return;
skb = buf->os_buf;
prefetch(skb->data - NET_IP_ALIGN);
pci_unmap_single(enic->pdev, buf->dma_addr,
buf->len, PCI_DMA_FROMDEVICE);
cq_enet_rq_desc_dec((struct cq_enet_rq_desc *)cq_desc,
&type, &color, &q_number, &completed_index,
@ -1011,6 +1047,13 @@ static void enic_rq_indicate_buf(struct vnic_rq *rq,
/* Good receive
*/
if (!enic_rxcopybreak(netdev, &skb, buf, bytes_written)) {
buf->os_buf = NULL;
pci_unmap_single(enic->pdev, buf->dma_addr, buf->len,
PCI_DMA_FROMDEVICE);
}
prefetch(skb->data - NET_IP_ALIGN);
skb_put(skb, bytes_written);
skb->protocol = eth_type_trans(skb, netdev);
skb_record_rx_queue(skb, q_number);
@ -2531,6 +2574,7 @@ static int enic_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
dev_err(dev, "Cannot register net device, aborting\n");
goto err_out_dev_deinit;
}
enic->rx_copybreak = RX_COPYBREAK_DEFAULT;
return 0;