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net: fec: implement rx_copybreak to improve rx performance
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- Copy short frames and keep the buffers mapped, re-allocate skb instead of
  memory copy for long frames.
- Add support for setting/getting rx_copybreak using generic ethtool tunable

Changes V3:
* As Eric Dumazet's suggestion that removing the copybreak module parameter
  and only keep the ethtool API support for rx_copybreak.

Changes V2:
* Implements rx_copybreak
* Rx_copybreak provides module parameter to change this value
* Add tunable_ops support for rx_copybreak

Signed-off-by: Fugang Duan <B38611@freescale.com>
Signed-off-by: Frank Li <Frank.Li@freescale.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Nimrod Andy authored and David S. Miller committed Oct 2, 2014
1 parent ce1a4ea commit 1b7bde6
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Showing 2 changed files with 145 additions and 65 deletions.
2 changes: 2 additions & 0 deletions drivers/net/ethernet/freescale/fec.h
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Original file line number Diff line number Diff line change
Expand Up @@ -482,6 +482,8 @@ struct fec_enet_private {
unsigned int tx_pkts_itr;
unsigned int tx_time_itr;
unsigned int itr_clk_rate;

u32 rx_copybreak;
};

void fec_ptp_init(struct platform_device *pdev);
Expand Down
208 changes: 143 additions & 65 deletions drivers/net/ethernet/freescale/fec_main.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -236,6 +236,8 @@ MODULE_PARM_DESC(macaddr, "FEC Ethernet MAC address");
#define FEC_PAUSE_FLAG_AUTONEG 0x1
#define FEC_PAUSE_FLAG_ENABLE 0x2

#define COPYBREAK_DEFAULT 256

#define TSO_HEADER_SIZE 128
/* Max number of allowed TCP segments for software TSO */
#define FEC_MAX_TSO_SEGS 100
Expand Down Expand Up @@ -1322,6 +1324,50 @@ fec_enet_tx(struct net_device *ndev)
return;
}

static int
fec_enet_new_rxbdp(struct net_device *ndev, struct bufdesc *bdp, struct sk_buff *skb)
{
struct fec_enet_private *fep = netdev_priv(ndev);
int off;

off = ((unsigned long)skb->data) & fep->rx_align;
if (off)
skb_reserve(skb, fep->rx_align + 1 - off);

bdp->cbd_bufaddr = dma_map_single(&fep->pdev->dev, skb->data,
FEC_ENET_RX_FRSIZE - fep->rx_align,
DMA_FROM_DEVICE);
if (dma_mapping_error(&fep->pdev->dev, bdp->cbd_bufaddr)) {
if (net_ratelimit())
netdev_err(ndev, "Rx DMA memory map failed\n");
return -ENOMEM;
}

return 0;
}

static bool fec_enet_copybreak(struct net_device *ndev, struct sk_buff **skb,
struct bufdesc *bdp, u32 length)
{
struct fec_enet_private *fep = netdev_priv(ndev);
struct sk_buff *new_skb;

if (length > fep->rx_copybreak)
return false;

new_skb = netdev_alloc_skb(ndev, length);
if (!new_skb)
return false;

dma_sync_single_for_cpu(&fep->pdev->dev, bdp->cbd_bufaddr,
FEC_ENET_RX_FRSIZE - fep->rx_align,
DMA_FROM_DEVICE);
memcpy(new_skb->data, (*skb)->data, length);
*skb = new_skb;

return true;
}

/* During a receive, the cur_rx points to the current incoming buffer.
* When we update through the ring, if the next incoming buffer has
* not been given to the system, we just set the empty indicator,
Expand All @@ -1336,14 +1382,16 @@ fec_enet_rx_queue(struct net_device *ndev, int budget, u16 queue_id)
struct fec_enet_priv_rx_q *rxq;
struct bufdesc *bdp;
unsigned short status;
struct sk_buff *skb;
struct sk_buff *skb_new = NULL;
struct sk_buff *skb;
ushort pkt_len;
__u8 *data;
int pkt_received = 0;
struct bufdesc_ex *ebdp = NULL;
bool vlan_packet_rcvd = false;
u16 vlan_tag;
int index = 0;
bool is_copybreak;

#ifdef CONFIG_M532x
flush_cache_all();
Expand Down Expand Up @@ -1401,11 +1449,27 @@ fec_enet_rx_queue(struct net_device *ndev, int budget, u16 queue_id)
ndev->stats.rx_bytes += pkt_len;

index = fec_enet_get_bd_index(rxq->rx_bd_base, bdp, fep);
data = rxq->rx_skbuff[index]->data;
dma_sync_single_for_cpu(&fep->pdev->dev, bdp->cbd_bufaddr,
FEC_ENET_RX_FRSIZE - fep->rx_align,
DMA_FROM_DEVICE);
skb = rxq->rx_skbuff[index];

/* The packet length includes FCS, but we don't want to
* include that when passing upstream as it messes up
* bridging applications.
*/
is_copybreak = fec_enet_copybreak(ndev, &skb, bdp, pkt_len - 4);
if (!is_copybreak) {
skb_new = netdev_alloc_skb(ndev, FEC_ENET_RX_FRSIZE);
if (unlikely(!skb_new)) {
ndev->stats.rx_dropped++;
goto rx_processing_done;
}
dma_unmap_single(&fep->pdev->dev, bdp->cbd_bufaddr,
FEC_ENET_RX_FRSIZE - fep->rx_align,
DMA_FROM_DEVICE);
}

prefetch(skb->data - NET_IP_ALIGN);
skb_put(skb, pkt_len - 4);
data = skb->data;
if (id_entry->driver_data & FEC_QUIRK_SWAP_FRAME)
swap_buffer(data, pkt_len);

Expand All @@ -1422,62 +1486,48 @@ fec_enet_rx_queue(struct net_device *ndev, int budget, u16 queue_id)
struct vlan_hdr *vlan_header =
(struct vlan_hdr *) (data + ETH_HLEN);
vlan_tag = ntohs(vlan_header->h_vlan_TCI);
pkt_len -= VLAN_HLEN;

vlan_packet_rcvd = true;

skb_copy_to_linear_data_offset(skb, VLAN_HLEN,
data, (2 * ETH_ALEN));
skb_pull(skb, VLAN_HLEN);
}

/* This does 16 byte alignment, exactly what we need.
* The packet length includes FCS, but we don't want to
* include that when passing upstream as it messes up
* bridging applications.
*/
skb = netdev_alloc_skb(ndev, pkt_len - 4 + NET_IP_ALIGN);
skb->protocol = eth_type_trans(skb, ndev);

if (unlikely(!skb)) {
ndev->stats.rx_dropped++;
} else {
int payload_offset = (2 * ETH_ALEN);
skb_reserve(skb, NET_IP_ALIGN);
skb_put(skb, pkt_len - 4); /* Make room */

/* Extract the frame data without the VLAN header. */
skb_copy_to_linear_data(skb, data, (2 * ETH_ALEN));
if (vlan_packet_rcvd)
payload_offset = (2 * ETH_ALEN) + VLAN_HLEN;
skb_copy_to_linear_data_offset(skb, (2 * ETH_ALEN),
data + payload_offset,
pkt_len - 4 - (2 * ETH_ALEN));

skb->protocol = eth_type_trans(skb, ndev);

/* Get receive timestamp from the skb */
if (fep->hwts_rx_en && fep->bufdesc_ex)
fec_enet_hwtstamp(fep, ebdp->ts,
skb_hwtstamps(skb));

if (fep->bufdesc_ex &&
(fep->csum_flags & FLAG_RX_CSUM_ENABLED)) {
if (!(ebdp->cbd_esc & FLAG_RX_CSUM_ERROR)) {
/* don't check it */
skb->ip_summed = CHECKSUM_UNNECESSARY;
} else {
skb_checksum_none_assert(skb);
}
/* Get receive timestamp from the skb */
if (fep->hwts_rx_en && fep->bufdesc_ex)
fec_enet_hwtstamp(fep, ebdp->ts,
skb_hwtstamps(skb));

if (fep->bufdesc_ex &&
(fep->csum_flags & FLAG_RX_CSUM_ENABLED)) {
if (!(ebdp->cbd_esc & FLAG_RX_CSUM_ERROR)) {
/* don't check it */
skb->ip_summed = CHECKSUM_UNNECESSARY;
} else {
skb_checksum_none_assert(skb);
}
}

/* Handle received VLAN packets */
if (vlan_packet_rcvd)
__vlan_hwaccel_put_tag(skb,
htons(ETH_P_8021Q),
vlan_tag);
/* Handle received VLAN packets */
if (vlan_packet_rcvd)
__vlan_hwaccel_put_tag(skb,
htons(ETH_P_8021Q),
vlan_tag);

napi_gro_receive(&fep->napi, skb);
napi_gro_receive(&fep->napi, skb);

if (is_copybreak) {
dma_sync_single_for_device(&fep->pdev->dev, bdp->cbd_bufaddr,
FEC_ENET_RX_FRSIZE - fep->rx_align,
DMA_FROM_DEVICE);
} else {
rxq->rx_skbuff[index] = skb_new;
fec_enet_new_rxbdp(ndev, bdp, skb_new);
}

dma_sync_single_for_device(&fep->pdev->dev, bdp->cbd_bufaddr,
FEC_ENET_RX_FRSIZE - fep->rx_align,
DMA_FROM_DEVICE);
rx_processing_done:
/* Clear the status flags for this buffer */
status &= ~BD_ENET_RX_STATS;
Expand Down Expand Up @@ -2392,6 +2442,44 @@ static void fec_enet_itr_coal_init(struct net_device *ndev)
fec_enet_set_coalesce(ndev, &ec);
}

static int fec_enet_get_tunable(struct net_device *netdev,
const struct ethtool_tunable *tuna,
void *data)
{
struct fec_enet_private *fep = netdev_priv(netdev);
int ret = 0;

switch (tuna->id) {
case ETHTOOL_RX_COPYBREAK:
*(u32 *)data = fep->rx_copybreak;
break;
default:
ret = -EINVAL;
break;
}

return ret;
}

static int fec_enet_set_tunable(struct net_device *netdev,
const struct ethtool_tunable *tuna,
const void *data)
{
struct fec_enet_private *fep = netdev_priv(netdev);
int ret = 0;

switch (tuna->id) {
case ETHTOOL_RX_COPYBREAK:
fep->rx_copybreak = *(u32 *)data;
break;
default:
ret = -EINVAL;
break;
}

return ret;
}

static const struct ethtool_ops fec_enet_ethtool_ops = {
.get_settings = fec_enet_get_settings,
.set_settings = fec_enet_set_settings,
Expand All @@ -2408,6 +2496,8 @@ static const struct ethtool_ops fec_enet_ethtool_ops = {
.get_sset_count = fec_enet_get_sset_count,
#endif
.get_ts_info = fec_enet_get_ts_info,
.get_tunable = fec_enet_get_tunable,
.set_tunable = fec_enet_set_tunable,
};

static int fec_enet_ioctl(struct net_device *ndev, struct ifreq *rq, int cmd)
Expand Down Expand Up @@ -2553,33 +2643,20 @@ fec_enet_alloc_rxq_buffers(struct net_device *ndev, unsigned int queue)
struct sk_buff *skb;
struct bufdesc *bdp;
struct fec_enet_priv_rx_q *rxq;
unsigned int off;

rxq = fep->rx_queue[queue];
bdp = rxq->rx_bd_base;
for (i = 0; i < rxq->rx_ring_size; i++) {
dma_addr_t addr;

skb = netdev_alloc_skb(ndev, FEC_ENET_RX_FRSIZE);
if (!skb)
goto err_alloc;

off = ((unsigned long)skb->data) & fep->rx_align;
if (off)
skb_reserve(skb, fep->rx_align + 1 - off);

addr = dma_map_single(&fep->pdev->dev, skb->data,
FEC_ENET_RX_FRSIZE - fep->rx_align, DMA_FROM_DEVICE);

if (dma_mapping_error(&fep->pdev->dev, addr)) {
if (fec_enet_new_rxbdp(ndev, bdp, skb)) {
dev_kfree_skb(skb);
if (net_ratelimit())
netdev_err(ndev, "Rx DMA memory map failed\n");
goto err_alloc;
}

rxq->rx_skbuff[i] = skb;
bdp->cbd_bufaddr = addr;
bdp->cbd_sc = BD_ENET_RX_EMPTY;

if (fep->bufdesc_ex) {
Expand Down Expand Up @@ -3240,6 +3317,7 @@ fec_probe(struct platform_device *pdev)
if (fep->bufdesc_ex && fep->ptp_clock)
netdev_info(ndev, "registered PHC device %d\n", fep->dev_id);

fep->rx_copybreak = COPYBREAK_DEFAULT;
INIT_WORK(&fep->tx_timeout_work, fec_enet_timeout_work);
return 0;

Expand Down

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