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[PATCH] S2io: Performance improvements
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Hi,
This patch relates to mostly performance related changes.
1. Fixed incorrect computation of PANIC level in rx_buffer_level().
2. Removed unnecessary PIOs(read/write of tx_traffic_int and
   rx_traffic_int) from interrupt handler and removed read of
   general_int_status register from xmit routine.
3. Enable two-buffer mode(for Rx path) automatically for SGI
   systems. This improves Rx performance dramatically on
   SGI systems.

Signed-off-by: Ravinandan Arakali <ravinandan.arakali@neterion.com>
Signed-off-by: Raghavendra Koushik <raghavendra.koushik@neterion.com>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>
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raghavendra.koushik@neterion.com authored and Jeff Garzik committed Aug 11, 2005
1 parent 1ddc50d commit fe11363
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Showing 2 changed files with 24 additions and 27 deletions.
46 changes: 19 additions & 27 deletions drivers/net/s2io.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -100,8 +100,7 @@ static inline int rx_buffer_level(nic_t * sp, int rxb_size, int ring)
mac_control = &sp->mac_control;
if ((mac_control->rings[ring].pkt_cnt - rxb_size) > 16) {
level = LOW;
if ((mac_control->rings[ring].pkt_cnt - rxb_size) <
MAX_RXDS_PER_BLOCK) {
if (rxb_size <= MAX_RXDS_PER_BLOCK) {
level = PANIC;
}
}
Expand Down Expand Up @@ -2193,30 +2192,20 @@ static void rx_intr_handler(ring_info_t *ring_data)
{
nic_t *nic = ring_data->nic;
struct net_device *dev = (struct net_device *) nic->dev;
XENA_dev_config_t __iomem *bar0 = nic->bar0;
int get_block, get_offset, put_block, put_offset, ring_bufs;
rx_curr_get_info_t get_info, put_info;
RxD_t *rxdp;
struct sk_buff *skb;
#ifndef CONFIG_S2IO_NAPI
int pkt_cnt = 0;
#endif
register u64 val64;

spin_lock(&nic->rx_lock);
if (atomic_read(&nic->card_state) == CARD_DOWN) {
DBG_PRINT(ERR_DBG, "%s: %s going down for reset\n",
__FUNCTION__, dev->name);
spin_unlock(&nic->rx_lock);
}

/*
* rx_traffic_int reg is an R1 register, hence we read and write
* back the same value in the register to clear it
*/
val64 = readq(&bar0->tx_traffic_int);
writeq(val64, &bar0->tx_traffic_int);

get_info = ring_data->rx_curr_get_info;
get_block = get_info.block_index;
put_info = ring_data->rx_curr_put_info;
Expand Down Expand Up @@ -2312,20 +2301,11 @@ static void rx_intr_handler(ring_info_t *ring_data)
static void tx_intr_handler(fifo_info_t *fifo_data)
{
nic_t *nic = fifo_data->nic;
XENA_dev_config_t __iomem *bar0 = nic->bar0;
struct net_device *dev = (struct net_device *) nic->dev;
tx_curr_get_info_t get_info, put_info;
struct sk_buff *skb;
TxD_t *txdlp;
u16 j, frg_cnt;
register u64 val64 = 0;

/*
* tx_traffic_int reg is an R1 register, hence we read and write
* back the same value in the register to clear it
*/
val64 = readq(&bar0->tx_traffic_int);
writeq(val64, &bar0->tx_traffic_int);

get_info = fifo_data->tx_curr_get_info;
put_info = fifo_data->tx_curr_put_info;
Expand Down Expand Up @@ -2818,7 +2798,6 @@ int s2io_xmit(struct sk_buff *skb, struct net_device *dev)
#endif
mac_info_t *mac_control;
struct config_param *config;
XENA_dev_config_t __iomem *bar0 = sp->bar0;

mac_control = &sp->mac_control;
config = &sp->config;
Expand Down Expand Up @@ -2870,7 +2849,6 @@ int s2io_xmit(struct sk_buff *skb, struct net_device *dev)
}

txdp->Control_2 |= config->tx_intr_type;

txdp->Control_1 |= (TXD_BUFFER0_SIZE(frg_len) |
TXD_GATHER_CODE_FIRST);
txdp->Control_1 |= TXD_LIST_OWN_XENA;
Expand All @@ -2890,6 +2868,8 @@ int s2io_xmit(struct sk_buff *skb, struct net_device *dev)
val64 = mac_control->fifos[queue].list_info[put_off].list_phy_addr;
writeq(val64, &tx_fifo->TxDL_Pointer);

wmb();

val64 = (TX_FIFO_LAST_TXD_NUM(frg_cnt) | TX_FIFO_FIRST_LIST |
TX_FIFO_LAST_LIST);

Expand All @@ -2899,9 +2879,6 @@ int s2io_xmit(struct sk_buff *skb, struct net_device *dev)
#endif
writeq(val64, &tx_fifo->List_Control);

/* Perform a PCI read to flush previous writes */
val64 = readq(&bar0->general_int_status);

put_off++;
put_off %= mac_control->fifos[queue].tx_curr_put_info.fifo_len + 1;
mac_control->fifos[queue].tx_curr_put_info.offset = put_off;
Expand Down Expand Up @@ -2940,7 +2917,7 @@ static irqreturn_t s2io_isr(int irq, void *dev_id, struct pt_regs *regs)
nic_t *sp = dev->priv;
XENA_dev_config_t __iomem *bar0 = sp->bar0;
int i;
u64 reason = 0;
u64 reason = 0, val64;
mac_info_t *mac_control;
struct config_param *config;

Expand Down Expand Up @@ -2978,6 +2955,13 @@ static irqreturn_t s2io_isr(int irq, void *dev_id, struct pt_regs *regs)
#else
/* If Intr is because of Rx Traffic */
if (reason & GEN_INTR_RXTRAFFIC) {
/*
* rx_traffic_int reg is an R1 register, writing all 1's
* will ensure that the actual interrupt causing bit get's
* cleared and hence a read can be avoided.
*/
val64 = 0xFFFFFFFFFFFFFFFFULL;
writeq(val64, &bar0->rx_traffic_int);
for (i = 0; i < config->rx_ring_num; i++) {
rx_intr_handler(&mac_control->rings[i]);
}
Expand All @@ -2986,6 +2970,14 @@ static irqreturn_t s2io_isr(int irq, void *dev_id, struct pt_regs *regs)

/* If Intr is because of Tx Traffic */
if (reason & GEN_INTR_TXTRAFFIC) {
/*
* tx_traffic_int reg is an R1 register, writing all 1's
* will ensure that the actual interrupt causing bit get's
* cleared and hence a read can be avoided.
*/
val64 = 0xFFFFFFFFFFFFFFFFULL;
writeq(val64, &bar0->tx_traffic_int);

for (i = 0; i < config->tx_fifo_num; i++)
tx_intr_handler(&mac_control->fifos[i]);
}
Expand Down
5 changes: 5 additions & 0 deletions drivers/net/s2io.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -13,6 +13,11 @@
#ifndef _S2IO_H
#define _S2IO_H

/* Enable 2 buffer mode by default for SGI system */
#ifdef CONFIG_IA64_SGI_SN2
#define CONFIG_2BUFF_MODE
#endif

#define TBD 0
#define BIT(loc) (0x8000000000000000ULL >> (loc))
#define vBIT(val, loc, sz) (((u64)val) << (64-loc-sz))
Expand Down

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