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forcedeth: tx data path optimization
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This patch optimizes the tx data paths and cleans up the code (removes
vlan from descr1/2 since only valid for desc3, changes to make code
easier to read, etc).

Signed-Off-By: Ayaz Abdulla <aabdulla@nvidia.com>

Signed-off-by: Jeff Garzik <jeff@garzik.org>
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Ayaz Abdulla authored and Jeff Garzik committed Feb 5, 2007
1 parent aaa37d2 commit 445583b
Showing 1 changed file with 58 additions and 57 deletions.
115 changes: 58 additions & 57 deletions drivers/net/forcedeth.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1563,7 +1563,6 @@ static int nv_start_xmit(struct sk_buff *skb, struct net_device *dev)
u32 size = skb->len-skb->data_len;
u32 entries = (size >> NV_TX2_TSO_MAX_SHIFT) + ((size & (NV_TX2_TSO_MAX_SIZE-1)) ? 1 : 0);
u32 empty_slots;
u32 tx_flags_vlan = 0;
struct ring_desc* put_tx;
struct ring_desc* start_tx;
struct ring_desc* prev_tx;
Expand All @@ -1576,7 +1575,7 @@ static int nv_start_xmit(struct sk_buff *skb, struct net_device *dev)
}

empty_slots = nv_get_empty_tx_slots(np);
if (empty_slots <= entries) {
if (unlikely(empty_slots <= entries)) {
spin_lock_irq(&np->lock);
netif_stop_queue(dev);
np->tx_stop = 1;
Expand All @@ -1596,12 +1595,13 @@ static int nv_start_xmit(struct sk_buff *skb, struct net_device *dev)
np->put_tx_ctx->dma_len = bcnt;
put_tx->buf = cpu_to_le32(np->put_tx_ctx->dma);
put_tx->flaglen = cpu_to_le32((bcnt-1) | tx_flags);

tx_flags = np->tx_flags;
offset += bcnt;
size -= bcnt;
if (put_tx++ == np->last_tx.orig)
if (unlikely(put_tx++ == np->last_tx.orig))
put_tx = np->first_tx.orig;
if (np->put_tx_ctx++ == np->last_tx_ctx)
if (unlikely(np->put_tx_ctx++ == np->last_tx_ctx))
np->put_tx_ctx = np->first_tx_ctx;
} while (size);

Expand All @@ -1618,14 +1618,14 @@ static int nv_start_xmit(struct sk_buff *skb, struct net_device *dev)
np->put_tx_ctx->dma = pci_map_page(np->pci_dev, frag->page, frag->page_offset+offset, bcnt,
PCI_DMA_TODEVICE);
np->put_tx_ctx->dma_len = bcnt;

put_tx->buf = cpu_to_le32(np->put_tx_ctx->dma);
put_tx->flaglen = cpu_to_le32((bcnt-1) | tx_flags);

offset += bcnt;
size -= bcnt;
if (put_tx++ == np->last_tx.orig)
if (unlikely(put_tx++ == np->last_tx.orig))
put_tx = np->first_tx.orig;
if (np->put_tx_ctx++ == np->last_tx_ctx)
if (unlikely(np->put_tx_ctx++ == np->last_tx_ctx))
np->put_tx_ctx = np->first_tx_ctx;
} while (size);
}
Expand All @@ -1642,11 +1642,6 @@ static int nv_start_xmit(struct sk_buff *skb, struct net_device *dev)
tx_flags_extra = skb->ip_summed == CHECKSUM_PARTIAL ?
NV_TX2_CHECKSUM_L3 | NV_TX2_CHECKSUM_L4 : 0;

/* vlan tag */
if (np->vlangrp && vlan_tx_tag_present(skb)) {
tx_flags_vlan = NV_TX3_VLAN_TAG_PRESENT | vlan_tx_tag_get(skb);
}

spin_lock_irq(&np->lock);

/* set tx flags */
Expand All @@ -1669,23 +1664,21 @@ static int nv_start_xmit(struct sk_buff *skb, struct net_device *dev)

dev->trans_start = jiffies;
writel(NVREG_TXRXCTL_KICK|np->txrxctl_bits, get_hwbase(dev) + NvRegTxRxControl);
pci_push(get_hwbase(dev));
return NETDEV_TX_OK;
}

static int nv_start_xmit_optimized(struct sk_buff *skb, struct net_device *dev)
{
struct fe_priv *np = netdev_priv(dev);
u32 tx_flags = 0;
u32 tx_flags_extra = NV_TX2_LASTPACKET;
u32 tx_flags_extra;
unsigned int fragments = skb_shinfo(skb)->nr_frags;
unsigned int i;
u32 offset = 0;
u32 bcnt;
u32 size = skb->len-skb->data_len;
u32 entries = (size >> NV_TX2_TSO_MAX_SHIFT) + ((size & (NV_TX2_TSO_MAX_SIZE-1)) ? 1 : 0);
u32 empty_slots;
u32 tx_flags_vlan = 0;
struct ring_desc_ex* put_tx;
struct ring_desc_ex* start_tx;
struct ring_desc_ex* prev_tx;
Expand All @@ -1698,7 +1691,7 @@ static int nv_start_xmit_optimized(struct sk_buff *skb, struct net_device *dev)
}

empty_slots = nv_get_empty_tx_slots(np);
if (empty_slots <= entries) {
if (unlikely(empty_slots <= entries)) {
spin_lock_irq(&np->lock);
netif_stop_queue(dev);
np->tx_stop = 1;
Expand All @@ -1719,12 +1712,13 @@ static int nv_start_xmit_optimized(struct sk_buff *skb, struct net_device *dev)
put_tx->bufhigh = cpu_to_le64(np->put_tx_ctx->dma) >> 32;
put_tx->buflow = cpu_to_le64(np->put_tx_ctx->dma) & 0x0FFFFFFFF;
put_tx->flaglen = cpu_to_le32((bcnt-1) | tx_flags);
tx_flags = np->tx_flags;

tx_flags = NV_TX2_VALID;
offset += bcnt;
size -= bcnt;
if (put_tx++ == np->last_tx.ex)
if (unlikely(put_tx++ == np->last_tx.ex))
put_tx = np->first_tx.ex;
if (np->put_tx_ctx++ == np->last_tx_ctx)
if (unlikely(np->put_tx_ctx++ == np->last_tx_ctx))
np->put_tx_ctx = np->first_tx_ctx;
} while (size);

Expand All @@ -1741,21 +1735,21 @@ static int nv_start_xmit_optimized(struct sk_buff *skb, struct net_device *dev)
np->put_tx_ctx->dma = pci_map_page(np->pci_dev, frag->page, frag->page_offset+offset, bcnt,
PCI_DMA_TODEVICE);
np->put_tx_ctx->dma_len = bcnt;

put_tx->bufhigh = cpu_to_le64(np->put_tx_ctx->dma) >> 32;
put_tx->buflow = cpu_to_le64(np->put_tx_ctx->dma) & 0x0FFFFFFFF;
put_tx->flaglen = cpu_to_le32((bcnt-1) | tx_flags);

offset += bcnt;
size -= bcnt;
if (put_tx++ == np->last_tx.ex)
if (unlikely(put_tx++ == np->last_tx.ex))
put_tx = np->first_tx.ex;
if (np->put_tx_ctx++ == np->last_tx_ctx)
if (unlikely(np->put_tx_ctx++ == np->last_tx_ctx))
np->put_tx_ctx = np->first_tx_ctx;
} while (size);
}

/* set last fragment flag */
prev_tx->flaglen |= cpu_to_le32(tx_flags_extra);
prev_tx->flaglen |= cpu_to_le32(NV_TX2_LASTPACKET);

/* save skb in this slot's context area */
prev_tx_ctx->skb = skb;
Expand All @@ -1767,14 +1761,18 @@ static int nv_start_xmit_optimized(struct sk_buff *skb, struct net_device *dev)
NV_TX2_CHECKSUM_L3 | NV_TX2_CHECKSUM_L4 : 0;

/* vlan tag */
if (np->vlangrp && vlan_tx_tag_present(skb)) {
tx_flags_vlan = NV_TX3_VLAN_TAG_PRESENT | vlan_tx_tag_get(skb);
if (likely(!np->vlangrp)) {
start_tx->txvlan = 0;
} else {
if (vlan_tx_tag_present(skb))
start_tx->txvlan = cpu_to_le32(NV_TX3_VLAN_TAG_PRESENT | vlan_tx_tag_get(skb));
else
start_tx->txvlan = 0;
}

spin_lock_irq(&np->lock);

/* set tx flags */
start_tx->txvlan = cpu_to_le32(tx_flags_vlan);
start_tx->flaglen |= cpu_to_le32(tx_flags | tx_flags_extra);
np->put_tx.ex = put_tx;

Expand All @@ -1794,7 +1792,6 @@ static int nv_start_xmit_optimized(struct sk_buff *skb, struct net_device *dev)

dev->trans_start = jiffies;
writel(NVREG_TXRXCTL_KICK|np->txrxctl_bits, get_hwbase(dev) + NvRegTxRxControl);
pci_push(get_hwbase(dev));
return NETDEV_TX_OK;
}

Expand All @@ -1807,54 +1804,56 @@ static void nv_tx_done(struct net_device *dev)
{
struct fe_priv *np = netdev_priv(dev);
u32 flags;
struct sk_buff *skb;
struct ring_desc* orig_get_tx = np->get_tx.orig;

while (np->get_tx.orig != np->put_tx.orig) {
flags = le32_to_cpu(np->get_tx.orig->flaglen);
while ((np->get_tx.orig != np->put_tx.orig) &&
!((flags = le32_to_cpu(np->get_tx.orig->flaglen)) & NV_TX_VALID)) {

dprintk(KERN_DEBUG "%s: nv_tx_done: flags 0x%x.\n",
dev->name, flags);
if (flags & NV_TX_VALID)
break;

pci_unmap_page(np->pci_dev, np->get_tx_ctx->dma,
np->get_tx_ctx->dma_len,
PCI_DMA_TODEVICE);
np->get_tx_ctx->dma = 0;

if (np->desc_ver == DESC_VER_1) {
if (flags & NV_TX_LASTPACKET) {
skb = np->get_tx_ctx->skb;
if (flags & (NV_TX_RETRYERROR|NV_TX_CARRIERLOST|NV_TX_LATECOLLISION|
NV_TX_UNDERFLOW|NV_TX_ERROR)) {
if (flags & NV_TX_ERROR) {
if (flags & NV_TX_UNDERFLOW)
np->stats.tx_fifo_errors++;
if (flags & NV_TX_CARRIERLOST)
np->stats.tx_carrier_errors++;
np->stats.tx_errors++;
} else {
np->stats.tx_packets++;
np->stats.tx_bytes += skb->len;
np->stats.tx_bytes += np->get_tx_ctx->skb->len;
}
dev_kfree_skb_any(np->get_tx_ctx->skb);
np->get_tx_ctx->skb = NULL;
}
} else {
if (flags & NV_TX2_LASTPACKET) {
skb = np->get_tx_ctx->skb;
if (flags & (NV_TX2_RETRYERROR|NV_TX2_CARRIERLOST|NV_TX2_LATECOLLISION|
NV_TX2_UNDERFLOW|NV_TX2_ERROR)) {
if (flags & NV_TX2_ERROR) {
if (flags & NV_TX2_UNDERFLOW)
np->stats.tx_fifo_errors++;
if (flags & NV_TX2_CARRIERLOST)
np->stats.tx_carrier_errors++;
np->stats.tx_errors++;
} else {
np->stats.tx_packets++;
np->stats.tx_bytes += skb->len;
np->stats.tx_bytes += np->get_tx_ctx->skb->len;
}
dev_kfree_skb_any(np->get_tx_ctx->skb);
np->get_tx_ctx->skb = NULL;
}
}
nv_release_txskb(dev, np->get_tx_ctx);
if (np->get_tx.orig++ == np->last_tx.orig)
if (unlikely(np->get_tx.orig++ == np->last_tx.orig))
np->get_tx.orig = np->first_tx.orig;
if (np->get_tx_ctx++ == np->last_tx_ctx)
if (unlikely(np->get_tx_ctx++ == np->last_tx_ctx))
np->get_tx_ctx = np->first_tx_ctx;
}
if ((np->tx_stop == 1) && (np->get_tx.orig != orig_get_tx)) {
if (unlikely((np->tx_stop == 1) && (np->get_tx.orig != orig_get_tx))) {
np->tx_stop = 0;
netif_wake_queue(dev);
}
Expand All @@ -1864,37 +1863,39 @@ static void nv_tx_done_optimized(struct net_device *dev)
{
struct fe_priv *np = netdev_priv(dev);
u32 flags;
struct sk_buff *skb;
struct ring_desc_ex* orig_get_tx = np->get_tx.ex;

while (np->get_tx.ex == np->put_tx.ex) {
flags = le32_to_cpu(np->get_tx.ex->flaglen);
while ((np->get_tx.ex != np->put_tx.ex) &&
!((flags = le32_to_cpu(np->get_tx.ex->flaglen)) & NV_TX_VALID)) {

dprintk(KERN_DEBUG "%s: nv_tx_done_optimized: flags 0x%x.\n",
dev->name, flags);
if (flags & NV_TX_VALID)
break;

pci_unmap_page(np->pci_dev, np->get_tx_ctx->dma,
np->get_tx_ctx->dma_len,
PCI_DMA_TODEVICE);
np->get_tx_ctx->dma = 0;

if (flags & NV_TX2_LASTPACKET) {
skb = np->get_tx_ctx->skb;
if (flags & (NV_TX2_RETRYERROR|NV_TX2_CARRIERLOST|NV_TX2_LATECOLLISION|
NV_TX2_UNDERFLOW|NV_TX2_ERROR)) {
if (flags & NV_TX2_ERROR) {
if (flags & NV_TX2_UNDERFLOW)
np->stats.tx_fifo_errors++;
if (flags & NV_TX2_CARRIERLOST)
np->stats.tx_carrier_errors++;
np->stats.tx_errors++;
} else {
np->stats.tx_packets++;
np->stats.tx_bytes += skb->len;
np->stats.tx_bytes += np->get_tx_ctx->skb->len;
}
dev_kfree_skb_any(np->get_tx_ctx->skb);
np->get_tx_ctx->skb = NULL;
}
nv_release_txskb(dev, np->get_tx_ctx);
if (np->get_tx.ex++ == np->last_tx.ex)
if (unlikely(np->get_tx.ex++ == np->last_tx.ex))
np->get_tx.ex = np->first_tx.ex;
if (np->get_tx_ctx++ == np->last_tx_ctx)
if (unlikely(np->get_tx_ctx++ == np->last_tx_ctx))
np->get_tx_ctx = np->first_tx_ctx;
}
if ((np->tx_stop == 1) && (np->get_tx.ex != orig_get_tx)) {
if (unlikely((np->tx_stop == 1) && (np->get_tx.ex != orig_get_tx))) {
np->tx_stop = 0;
netif_wake_queue(dev);
}
Expand Down

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