[PATCH] [5/12] pasemi_mac: performance tweaks
Olof Johansson
olof at lixom.net
Thu Nov 29 13:56:41 EST 2007
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 at lixom.net>
---
drivers/net/pasemi_mac.c | 114 ++++++++++++++++++++++++++++-------------------
1 file changed, 68 insertions(+), 46 deletions(-)
Index: k.org/drivers/net/pasemi_mac.c
===================================================================
--- k.org.orig/drivers/net/pasemi_mac.c
+++ k.org/drivers/net/pasemi_mac.c
@@ -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 \
@@ -103,12 +103,12 @@ static void write_iob_reg(unsigned int r
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);
@@ -124,16 +124,26 @@ static void write_dma_reg(unsigned int r
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;
@@ -211,19 +221,18 @@ static int pasemi_get_mac_addr(struct pa
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);
@@ -233,7 +242,7 @@ static int pasemi_mac_unmap_tx_skb(struc
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);
@@ -277,7 +286,7 @@ static int pasemi_mac_setup_rx_resources
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;
@@ -291,7 +300,7 @@ static int pasemi_mac_setup_rx_resources
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;
@@ -316,7 +325,7 @@ out_chan:
}
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;
@@ -439,9 +448,10 @@ static void pasemi_mac_free_rx_resources
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;
@@ -492,7 +502,7 @@ static void pasemi_mac_replenish_rx_ring
(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
@@ -506,7 +516,7 @@ static void pasemi_mac_restart_rx_intr(s
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;
@@ -519,7 +529,8 @@ static void pasemi_mac_restart_tx_intr(s
}
-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;
@@ -537,7 +548,8 @@ static inline void pasemi_mac_rx_error(s
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;
@@ -553,19 +565,22 @@ static inline void pasemi_mac_tx_error(s
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);
@@ -575,6 +590,7 @@ static int pasemi_mac_clean_rx(struct pa
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))
@@ -596,12 +612,12 @@ static int pasemi_mac_clean_rx(struct pa
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 */
@@ -628,9 +644,6 @@ static int pasemi_mac_clean_rx(struct pa
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) >>
@@ -638,8 +651,11 @@ static int pasemi_mac_clean_rx(struct pa
} 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);
@@ -672,6 +688,9 @@ next:
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;
@@ -758,10 +777,10 @@ restart:
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))
@@ -789,7 +808,7 @@ static irqreturn_t pasemi_mac_rx_intr(in
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))
@@ -1158,6 +1177,7 @@ static int pasemi_mac_start_tx(struct sk
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;
@@ -1205,6 +1225,8 @@ static int pasemi_mac_start_tx(struct sk
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
@@ -1215,13 +1237,13 @@ static int pasemi_mac_start_tx(struct sk
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
@@ -1231,8 +1253,7 @@ static int pasemi_mac_start_tx(struct sk
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;
@@ -1255,7 +1276,7 @@ out_err_nolock:
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);
@@ -1317,7 +1338,8 @@ pasemi_mac_probe(struct pci_dev *pdev, c
netif_napi_add(dev, &mac->napi, pasemi_mac_poll, 64);
- dev->features = NETIF_F_HW_CSUM | NETIF_F_LLTX | NETIF_F_SG;
+ dev->features = NETIF_F_HW_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) {
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