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pasemi_mac: performance tweaks
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pasemi_mac: performance tweaks

* Seems like we do better with a smaller RX ring, probably because chances of
  still having the SKB cached are better
* Const-ify variables to get better code generation and fewer reloads
* Move prefetching around a little, and try to prefetch the whole SKB
* Set NETIF_F_HIGHDMA
* Misc other minor tweaks

Signed-off-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
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Olof Johansson authored and David S. Miller committed Jan 28, 2008
1 parent 34c2062 commit 5c15332
Showing 1 changed file with 68 additions and 46 deletions.
114 changes: 68 additions & 46 deletions drivers/net/pasemi_mac.c
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Original file line number Diff line number Diff line change
Expand Up @@ -56,7 +56,7 @@


/* Must be a power of two */
#define RX_RING_SIZE 4096
#define RX_RING_SIZE 1024
#define TX_RING_SIZE 4096

#define DEFAULT_MSG_ENABLE \
Expand Down Expand Up @@ -103,12 +103,12 @@ static void write_iob_reg(unsigned int reg, unsigned int val)
pasemi_write_iob_reg(reg, val);
}

static unsigned int read_mac_reg(struct pasemi_mac *mac, unsigned int reg)
static unsigned int read_mac_reg(const struct pasemi_mac *mac, unsigned int reg)
{
return pasemi_read_mac_reg(mac->dma_if, reg);
}

static void write_mac_reg(struct pasemi_mac *mac, unsigned int reg,
static void write_mac_reg(const struct pasemi_mac *mac, unsigned int reg,
unsigned int val)
{
pasemi_write_mac_reg(mac->dma_if, reg, val);
Expand All @@ -124,16 +124,26 @@ static void write_dma_reg(unsigned int reg, unsigned int val)
pasemi_write_dma_reg(reg, val);
}

static struct pasemi_mac_rxring *rx_ring(struct pasemi_mac *mac)
static struct pasemi_mac_rxring *rx_ring(const struct pasemi_mac *mac)
{
return mac->rx;
}

static struct pasemi_mac_txring *tx_ring(struct pasemi_mac *mac)
static struct pasemi_mac_txring *tx_ring(const struct pasemi_mac *mac)
{
return mac->tx;
}

static inline void prefetch_skb(const struct sk_buff *skb)
{
const void *d = skb;

prefetch(d);
prefetch(d+64);
prefetch(d+128);
prefetch(d+192);
}

static int mac_to_intf(struct pasemi_mac *mac)
{
struct pci_dev *pdev = mac->pdev;
Expand Down Expand Up @@ -211,19 +221,18 @@ static int pasemi_get_mac_addr(struct pasemi_mac *mac)

static int pasemi_mac_unmap_tx_skb(struct pasemi_mac *mac,
struct sk_buff *skb,
dma_addr_t *dmas)
const dma_addr_t *dmas)
{
int f;
int nfrags = skb_shinfo(skb)->nr_frags;
struct pci_dev *pdev = mac->dma_pdev;

pci_unmap_single(mac->dma_pdev, dmas[0], skb_headlen(skb),
PCI_DMA_TODEVICE);
pci_unmap_single(pdev, dmas[0], skb_headlen(skb), PCI_DMA_TODEVICE);

for (f = 0; f < nfrags; f++) {
skb_frag_t *frag = &skb_shinfo(skb)->frags[f];

pci_unmap_page(mac->dma_pdev, dmas[f+1], frag->size,
PCI_DMA_TODEVICE);
pci_unmap_page(pdev, dmas[f+1], frag->size, PCI_DMA_TODEVICE);
}
dev_kfree_skb_irq(skb);

Expand All @@ -233,7 +242,7 @@ static int pasemi_mac_unmap_tx_skb(struct pasemi_mac *mac,
return (nfrags + 3) & ~1;
}

static int pasemi_mac_setup_rx_resources(struct net_device *dev)
static int pasemi_mac_setup_rx_resources(const struct net_device *dev)
{
struct pasemi_mac_rxring *ring;
struct pasemi_mac *mac = netdev_priv(dev);
Expand Down Expand Up @@ -277,7 +286,7 @@ static int pasemi_mac_setup_rx_resources(struct net_device *dev)
PAS_DMA_RXCHAN_BASEU_BRBH(ring->chan.ring_dma >> 32) |
PAS_DMA_RXCHAN_BASEU_SIZ(RX_RING_SIZE >> 3));

cfg = PAS_DMA_RXCHAN_CFG_HBU(1);
cfg = PAS_DMA_RXCHAN_CFG_HBU(2);

if (translation_enabled())
cfg |= PAS_DMA_RXCHAN_CFG_CTR;
Expand All @@ -291,7 +300,7 @@ static int pasemi_mac_setup_rx_resources(struct net_device *dev)
PAS_DMA_RXINT_BASEU_BRBH(ring->buf_dma >> 32) |
PAS_DMA_RXINT_BASEU_SIZ(RX_RING_SIZE >> 3));

cfg = PAS_DMA_RXINT_CFG_DHL(1) | PAS_DMA_RXINT_CFG_L2 |
cfg = PAS_DMA_RXINT_CFG_DHL(2) | PAS_DMA_RXINT_CFG_L2 |
PAS_DMA_RXINT_CFG_LW | PAS_DMA_RXINT_CFG_RBP |
PAS_DMA_RXINT_CFG_HEN;

Expand All @@ -316,7 +325,7 @@ static int pasemi_mac_setup_rx_resources(struct net_device *dev)
}

static struct pasemi_mac_txring *
pasemi_mac_setup_tx_resources(struct net_device *dev)
pasemi_mac_setup_tx_resources(const struct net_device *dev)
{
struct pasemi_mac *mac = netdev_priv(dev);
u32 val;
Expand Down Expand Up @@ -439,9 +448,10 @@ static void pasemi_mac_free_rx_resources(struct pasemi_mac *mac)
mac->rx = NULL;
}

static void pasemi_mac_replenish_rx_ring(struct net_device *dev, int limit)
static void pasemi_mac_replenish_rx_ring(const struct net_device *dev,
const int limit)
{
struct pasemi_mac *mac = netdev_priv(dev);
const struct pasemi_mac *mac = netdev_priv(dev);
struct pasemi_mac_rxring *rx = rx_ring(mac);
int fill, count;

Expand Down Expand Up @@ -492,7 +502,7 @@ static void pasemi_mac_replenish_rx_ring(struct net_device *dev, int limit)
(RX_RING_SIZE - 1);
}

static void pasemi_mac_restart_rx_intr(struct pasemi_mac *mac)
static void pasemi_mac_restart_rx_intr(const struct pasemi_mac *mac)
{
unsigned int reg, pcnt;
/* Re-enable packet count interrupts: finally
Expand All @@ -506,7 +516,7 @@ static void pasemi_mac_restart_rx_intr(struct pasemi_mac *mac)
write_iob_reg(PAS_IOB_DMA_RXCH_RESET(mac->rx->chan.chno), reg);
}

static void pasemi_mac_restart_tx_intr(struct pasemi_mac *mac)
static void pasemi_mac_restart_tx_intr(const struct pasemi_mac *mac)
{
unsigned int reg, pcnt;

Expand All @@ -519,7 +529,8 @@ static void pasemi_mac_restart_tx_intr(struct pasemi_mac *mac)
}


static inline void pasemi_mac_rx_error(struct pasemi_mac *mac, u64 macrx)
static inline void pasemi_mac_rx_error(const struct pasemi_mac *mac,
const u64 macrx)
{
unsigned int rcmdsta, ccmdsta;
struct pasemi_dmachan *chan = &rx_ring(mac)->chan;
Expand All @@ -537,7 +548,8 @@ static inline void pasemi_mac_rx_error(struct pasemi_mac *mac, u64 macrx)
rcmdsta, ccmdsta);
}

static inline void pasemi_mac_tx_error(struct pasemi_mac *mac, u64 mactx)
static inline void pasemi_mac_tx_error(const struct pasemi_mac *mac,
const u64 mactx)
{
unsigned int cmdsta;
struct pasemi_dmachan *chan = &tx_ring(mac)->chan;
Expand All @@ -553,19 +565,22 @@ static inline void pasemi_mac_tx_error(struct pasemi_mac *mac, u64 mactx)
printk(KERN_ERR "pasemi_mac: tcmdsta 0x%08x\n", cmdsta);
}

static int pasemi_mac_clean_rx(struct pasemi_mac_rxring *rx, int limit)
static int pasemi_mac_clean_rx(struct pasemi_mac_rxring *rx,
const int limit)
{
struct pasemi_dmachan *chan = &rx->chan;
const struct pasemi_dmachan *chan = &rx->chan;
struct pasemi_mac *mac = rx->mac;
struct pci_dev *pdev = mac->dma_pdev;
unsigned int n;
int count;
int count, buf_index, tot_bytes, packets;
struct pasemi_mac_buffer *info;
struct sk_buff *skb;
unsigned int len;
u64 macrx;
u64 macrx, eval;
dma_addr_t dma;
int buf_index;
u64 eval;

tot_bytes = 0;
packets = 0;

spin_lock(&rx->lock);

Expand All @@ -575,6 +590,7 @@ static int pasemi_mac_clean_rx(struct pasemi_mac_rxring *rx, int limit)

for (count = 0; count < limit; count++) {
macrx = RX_DESC(rx, n);
prefetch(&RX_DESC(rx, n+4));

if ((macrx & XCT_MACRX_E) ||
(*chan->status & PAS_STATUS_ERROR))
Expand All @@ -596,12 +612,12 @@ static int pasemi_mac_clean_rx(struct pasemi_mac_rxring *rx, int limit)

skb = info->skb;

prefetch(skb);
prefetch(&skb->data_len);
prefetch_skb(skb);

len = (macrx & XCT_MACRX_LLEN_M) >> XCT_MACRX_LLEN_S;

pci_unmap_single(mac->dma_pdev, dma, len, PCI_DMA_FROMDEVICE);
pci_unmap_single(pdev, dma, BUF_SIZE-LOCAL_SKB_ALIGN,
PCI_DMA_FROMDEVICE);

if (macrx & XCT_MACRX_CRC) {
/* CRC error flagged */
Expand All @@ -628,18 +644,18 @@ static int pasemi_mac_clean_rx(struct pasemi_mac_rxring *rx, int limit)

info->dma = 0;

/* Don't include CRC */
skb_put(skb, len-4);

if (likely((macrx & XCT_MACRX_HTY_M) == XCT_MACRX_HTY_IPV4_OK)) {
skb->ip_summed = CHECKSUM_UNNECESSARY;
skb->csum = (macrx & XCT_MACRX_CSUM_M) >>
XCT_MACRX_CSUM_S;
} else
skb->ip_summed = CHECKSUM_NONE;

mac->netdev->stats.rx_bytes += len;
mac->netdev->stats.rx_packets++;
packets++;
tot_bytes += len;

/* Don't include CRC */
skb_put(skb, len-4);

skb->protocol = eth_type_trans(skb, mac->netdev);
netif_receive_skb(skb);
Expand Down Expand Up @@ -672,6 +688,9 @@ static int pasemi_mac_clean_rx(struct pasemi_mac_rxring *rx, int limit)

pasemi_mac_replenish_rx_ring(mac->netdev, count);

mac->netdev->stats.rx_bytes += tot_bytes;
mac->netdev->stats.rx_packets += packets;

spin_unlock(&rx_ring(mac)->lock);

return count;
Expand Down Expand Up @@ -758,10 +777,10 @@ static int pasemi_mac_clean_tx(struct pasemi_mac_txring *txring)

static irqreturn_t pasemi_mac_rx_intr(int irq, void *data)
{
struct pasemi_mac_rxring *rxring = data;
const struct pasemi_mac_rxring *rxring = data;
struct pasemi_mac *mac = rxring->mac;
struct net_device *dev = mac->netdev;
struct pasemi_dmachan *chan = &rxring->chan;
const struct pasemi_dmachan *chan = &rxring->chan;
unsigned int reg;

if (!(*chan->status & PAS_STATUS_CAUSE_M))
Expand Down Expand Up @@ -789,7 +808,7 @@ static irqreturn_t pasemi_mac_rx_intr(int irq, void *data)
static irqreturn_t pasemi_mac_tx_intr(int irq, void *data)
{
struct pasemi_mac_txring *txring = data;
struct pasemi_dmachan *chan = &txring->chan;
const struct pasemi_dmachan *chan = &txring->chan;
unsigned int reg, pcnt;

if (!(*chan->status & PAS_STATUS_CAUSE_M))
Expand Down Expand Up @@ -1158,6 +1177,7 @@ static int pasemi_mac_start_tx(struct sk_buff *skb, struct net_device *dev)
unsigned int map_size[MAX_SKB_FRAGS+1];
unsigned long flags;
int i, nfrags;
int fill;

dflags = XCT_MACTX_O | XCT_MACTX_ST | XCT_MACTX_CRC_PAD;

Expand Down Expand Up @@ -1205,6 +1225,8 @@ static int pasemi_mac_start_tx(struct sk_buff *skb, struct net_device *dev)

spin_lock_irqsave(&txring->lock, flags);

fill = txring->next_to_fill;

/* Avoid stepping on the same cache line that the DMA controller
* is currently about to send, so leave at least 8 words available.
* Total free space needed is mactx + fragments + 8
Expand All @@ -1215,13 +1237,13 @@ static int pasemi_mac_start_tx(struct sk_buff *skb, struct net_device *dev)
goto out_err;
}

TX_DESC(txring, txring->next_to_fill) = mactx;
txring->next_to_fill++;
TX_DESC_INFO(txring, txring->next_to_fill).skb = skb;
TX_DESC(txring, fill) = mactx;
fill++;
TX_DESC_INFO(txring, fill).skb = skb;
for (i = 0; i <= nfrags; i++) {
TX_DESC(txring, txring->next_to_fill+i) =
TX_DESC(txring, fill+i) =
XCT_PTR_LEN(map_size[i]) | XCT_PTR_ADDR(map[i]);
TX_DESC_INFO(txring, txring->next_to_fill+i).dma = map[i];
TX_DESC_INFO(txring, fill+i).dma = map[i];
}

/* We have to add an even number of 8-byte entries to the ring
Expand All @@ -1231,8 +1253,7 @@ static int pasemi_mac_start_tx(struct sk_buff *skb, struct net_device *dev)
if (nfrags & 1)
nfrags++;

txring->next_to_fill = (txring->next_to_fill + nfrags + 1) &
(TX_RING_SIZE-1);
txring->next_to_fill = (fill + nfrags + 1) & (TX_RING_SIZE-1);

dev->stats.tx_packets++;
dev->stats.tx_bytes += skb->len;
Expand All @@ -1255,7 +1276,7 @@ static int pasemi_mac_start_tx(struct sk_buff *skb, struct net_device *dev)

static void pasemi_mac_set_rx_mode(struct net_device *dev)
{
struct pasemi_mac *mac = netdev_priv(dev);
const struct pasemi_mac *mac = netdev_priv(dev);
unsigned int flags;

flags = read_mac_reg(mac, PAS_MAC_CFG_PCFG);
Expand Down Expand Up @@ -1317,7 +1338,8 @@ pasemi_mac_probe(struct pci_dev *pdev, const struct pci_device_id *ent)

netif_napi_add(dev, &mac->napi, pasemi_mac_poll, 64);

dev->features = NETIF_F_IP_CSUM | NETIF_F_LLTX | NETIF_F_SG;
dev->features = NETIF_F_IP_CSUM | NETIF_F_LLTX | NETIF_F_SG |
NETIF_F_HIGHDMA;

mac->dma_pdev = pci_get_device(PCI_VENDOR_ID_PASEMI, 0xa007, NULL);
if (!mac->dma_pdev) {
Expand Down

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