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amd-xgbe: Performance enhancements
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This patch provides some general performance enhancements for the
driver:
  - Modify the default coalescing settings (reduce usec, increase frames)
  - Change the AXI burst length to 256 bytes (default was 16 bytes which
    was smaller than a cache line)
  - Change the AXI cache settings to write-back/write-allocate which
    allocate cache entries for received packets during the DMA since the
    packet will be processed soon afterwards
  - Combine ioread/iowrite when disabling both the Tx and Rx interrupts
  - Change to processing the Tx/Rx channels in pairs
  - Only recycle the Rx descriptors when a threshold of dirty descriptors
    is reached

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Lendacky, Thomas authored and David S. Miller committed Jul 8, 2014
1 parent ff42606 commit 9867e8f
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Showing 4 changed files with 100 additions and 78 deletions.
2 changes: 2 additions & 0 deletions drivers/net/ethernet/amd/xgbe/xgbe-common.h
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Original file line number Diff line number Diff line change
Expand Up @@ -170,6 +170,8 @@
#define DMA_MR_SWR_WIDTH 1
#define DMA_SBMR_EAME_INDEX 11
#define DMA_SBMR_EAME_WIDTH 1
#define DMA_SBMR_BLEN_256_INDEX 7
#define DMA_SBMR_BLEN_256_WIDTH 1
#define DMA_SBMR_UNDEF_INDEX 0
#define DMA_SBMR_UNDEF_WIDTH 1

Expand Down
73 changes: 34 additions & 39 deletions drivers/net/ethernet/amd/xgbe/xgbe-dev.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1306,56 +1306,48 @@ static int xgbe_is_last_desc(struct xgbe_ring_desc *rdesc)
return XGMAC_GET_BITS_LE(rdesc->desc3, TX_NORMAL_DESC3, LD);
}

static void xgbe_save_interrupt_status(struct xgbe_channel *channel,
enum xgbe_int_state int_state)
static int xgbe_enable_int(struct xgbe_channel *channel,
enum xgbe_int int_id)
{
unsigned int dma_ch_ier;

if (int_state == XGMAC_INT_STATE_SAVE) {
channel->saved_ier = XGMAC_DMA_IOREAD(channel, DMA_CH_IER);
channel->saved_ier &= XGBE_DMA_INTERRUPT_MASK;
} else {
dma_ch_ier = XGMAC_DMA_IOREAD(channel, DMA_CH_IER);
dma_ch_ier |= channel->saved_ier;
XGMAC_DMA_IOWRITE(channel, DMA_CH_IER, dma_ch_ier);
}
}
dma_ch_ier = XGMAC_DMA_IOREAD(channel, DMA_CH_IER);

static int xgbe_enable_int(struct xgbe_channel *channel,
enum xgbe_int int_id)
{
switch (int_id) {
case XGMAC_INT_DMA_ISR_DC0IS:
XGMAC_DMA_IOWRITE_BITS(channel, DMA_CH_IER, TIE, 1);
break;
case XGMAC_INT_DMA_CH_SR_TI:
XGMAC_DMA_IOWRITE_BITS(channel, DMA_CH_IER, TIE, 1);
XGMAC_SET_BITS(dma_ch_ier, DMA_CH_IER, TIE, 1);
break;
case XGMAC_INT_DMA_CH_SR_TPS:
XGMAC_DMA_IOWRITE_BITS(channel, DMA_CH_IER, TXSE, 1);
XGMAC_SET_BITS(dma_ch_ier, DMA_CH_IER, TXSE, 1);
break;
case XGMAC_INT_DMA_CH_SR_TBU:
XGMAC_DMA_IOWRITE_BITS(channel, DMA_CH_IER, TBUE, 1);
XGMAC_SET_BITS(dma_ch_ier, DMA_CH_IER, TBUE, 1);
break;
case XGMAC_INT_DMA_CH_SR_RI:
XGMAC_DMA_IOWRITE_BITS(channel, DMA_CH_IER, RIE, 1);
XGMAC_SET_BITS(dma_ch_ier, DMA_CH_IER, RIE, 1);
break;
case XGMAC_INT_DMA_CH_SR_RBU:
XGMAC_DMA_IOWRITE_BITS(channel, DMA_CH_IER, RBUE, 1);
XGMAC_SET_BITS(dma_ch_ier, DMA_CH_IER, RBUE, 1);
break;
case XGMAC_INT_DMA_CH_SR_RPS:
XGMAC_DMA_IOWRITE_BITS(channel, DMA_CH_IER, RSE, 1);
XGMAC_SET_BITS(dma_ch_ier, DMA_CH_IER, RSE, 1);
break;
case XGMAC_INT_DMA_CH_SR_TI_RI:
XGMAC_SET_BITS(dma_ch_ier, DMA_CH_IER, TIE, 1);
XGMAC_SET_BITS(dma_ch_ier, DMA_CH_IER, RIE, 1);
break;
case XGMAC_INT_DMA_CH_SR_FBE:
XGMAC_DMA_IOWRITE_BITS(channel, DMA_CH_IER, FBEE, 1);
XGMAC_SET_BITS(dma_ch_ier, DMA_CH_IER, FBEE, 1);
break;
case XGMAC_INT_DMA_ALL:
xgbe_save_interrupt_status(channel, XGMAC_INT_STATE_RESTORE);
dma_ch_ier |= channel->saved_ier;
break;
default:
return -1;
}

XGMAC_DMA_IOWRITE(channel, DMA_CH_IER, dma_ch_ier);

return 0;
}

Expand All @@ -1364,42 +1356,44 @@ static int xgbe_disable_int(struct xgbe_channel *channel,
{
unsigned int dma_ch_ier;

dma_ch_ier = XGMAC_DMA_IOREAD(channel, DMA_CH_IER);

switch (int_id) {
case XGMAC_INT_DMA_ISR_DC0IS:
XGMAC_DMA_IOWRITE_BITS(channel, DMA_CH_IER, TIE, 0);
break;
case XGMAC_INT_DMA_CH_SR_TI:
XGMAC_DMA_IOWRITE_BITS(channel, DMA_CH_IER, TIE, 0);
XGMAC_SET_BITS(dma_ch_ier, DMA_CH_IER, TIE, 0);
break;
case XGMAC_INT_DMA_CH_SR_TPS:
XGMAC_DMA_IOWRITE_BITS(channel, DMA_CH_IER, TXSE, 0);
XGMAC_SET_BITS(dma_ch_ier, DMA_CH_IER, TXSE, 0);
break;
case XGMAC_INT_DMA_CH_SR_TBU:
XGMAC_DMA_IOWRITE_BITS(channel, DMA_CH_IER, TBUE, 0);
XGMAC_SET_BITS(dma_ch_ier, DMA_CH_IER, TBUE, 0);
break;
case XGMAC_INT_DMA_CH_SR_RI:
XGMAC_DMA_IOWRITE_BITS(channel, DMA_CH_IER, RIE, 0);
XGMAC_SET_BITS(dma_ch_ier, DMA_CH_IER, RIE, 0);
break;
case XGMAC_INT_DMA_CH_SR_RBU:
XGMAC_DMA_IOWRITE_BITS(channel, DMA_CH_IER, RBUE, 0);
XGMAC_SET_BITS(dma_ch_ier, DMA_CH_IER, RBUE, 0);
break;
case XGMAC_INT_DMA_CH_SR_RPS:
XGMAC_DMA_IOWRITE_BITS(channel, DMA_CH_IER, RSE, 0);
XGMAC_SET_BITS(dma_ch_ier, DMA_CH_IER, RSE, 0);
break;
case XGMAC_INT_DMA_CH_SR_TI_RI:
XGMAC_SET_BITS(dma_ch_ier, DMA_CH_IER, TIE, 0);
XGMAC_SET_BITS(dma_ch_ier, DMA_CH_IER, RIE, 0);
break;
case XGMAC_INT_DMA_CH_SR_FBE:
XGMAC_DMA_IOWRITE_BITS(channel, DMA_CH_IER, FBEE, 0);
XGMAC_SET_BITS(dma_ch_ier, DMA_CH_IER, FBEE, 0);
break;
case XGMAC_INT_DMA_ALL:
xgbe_save_interrupt_status(channel, XGMAC_INT_STATE_SAVE);

dma_ch_ier = XGMAC_DMA_IOREAD(channel, DMA_CH_IER);
channel->saved_ier = dma_ch_ier & XGBE_DMA_INTERRUPT_MASK;
dma_ch_ier &= ~XGBE_DMA_INTERRUPT_MASK;
XGMAC_DMA_IOWRITE(channel, DMA_CH_IER, dma_ch_ier);
break;
default:
return -1;
}

XGMAC_DMA_IOWRITE(channel, DMA_CH_IER, dma_ch_ier);

return 0;
}

Expand Down Expand Up @@ -1453,6 +1447,7 @@ static void xgbe_config_dma_bus(struct xgbe_prv_data *pdata)

/* Set the System Bus mode */
XGMAC_IOWRITE_BITS(pdata, DMA_SBMR, UNDEF, 1);
XGMAC_IOWRITE_BITS(pdata, DMA_SBMR, BLEN_256, 1);
}

static void xgbe_config_dma_cache(struct xgbe_prv_data *pdata)
Expand Down
91 changes: 58 additions & 33 deletions drivers/net/ethernet/amd/xgbe/xgbe-drv.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -156,33 +156,43 @@ static void xgbe_enable_rx_tx_ints(struct xgbe_prv_data *pdata)
{
struct xgbe_hw_if *hw_if = &pdata->hw_if;
struct xgbe_channel *channel;
enum xgbe_int int_id;
unsigned int i;

channel = pdata->channel;
for (i = 0; i < pdata->channel_count; i++, channel++) {
if (channel->tx_ring)
hw_if->enable_int(channel,
XGMAC_INT_DMA_CH_SR_TI);
if (channel->rx_ring)
hw_if->enable_int(channel,
XGMAC_INT_DMA_CH_SR_RI);
if (channel->tx_ring && channel->rx_ring)
int_id = XGMAC_INT_DMA_CH_SR_TI_RI;
else if (channel->tx_ring)
int_id = XGMAC_INT_DMA_CH_SR_TI;
else if (channel->rx_ring)
int_id = XGMAC_INT_DMA_CH_SR_RI;
else
continue;

hw_if->enable_int(channel, int_id);
}
}

static void xgbe_disable_rx_tx_ints(struct xgbe_prv_data *pdata)
{
struct xgbe_hw_if *hw_if = &pdata->hw_if;
struct xgbe_channel *channel;
enum xgbe_int int_id;
unsigned int i;

channel = pdata->channel;
for (i = 0; i < pdata->channel_count; i++, channel++) {
if (channel->tx_ring)
hw_if->disable_int(channel,
XGMAC_INT_DMA_CH_SR_TI);
if (channel->rx_ring)
hw_if->disable_int(channel,
XGMAC_INT_DMA_CH_SR_RI);
if (channel->tx_ring && channel->rx_ring)
int_id = XGMAC_INT_DMA_CH_SR_TI_RI;
else if (channel->tx_ring)
int_id = XGMAC_INT_DMA_CH_SR_TI;
else if (channel->rx_ring)
int_id = XGMAC_INT_DMA_CH_SR_RI;
else
continue;

hw_if->disable_int(channel, int_id);
}
}

Expand Down Expand Up @@ -1114,6 +1124,22 @@ struct net_device_ops *xgbe_get_netdev_ops(void)
return (struct net_device_ops *)&xgbe_netdev_ops;
}

static void xgbe_rx_refresh(struct xgbe_channel *channel)
{
struct xgbe_prv_data *pdata = channel->pdata;
struct xgbe_desc_if *desc_if = &pdata->desc_if;
struct xgbe_ring *ring = channel->rx_ring;
struct xgbe_ring_data *rdata;

desc_if->realloc_skb(channel);

/* Update the Rx Tail Pointer Register with address of
* the last cleaned entry */
rdata = XGBE_GET_DESC_DATA(ring, ring->rx.realloc_index - 1);
XGMAC_DMA_IOWRITE(channel, DMA_CH_RDTR_LO,
lower_32_bits(rdata->rdesc_dma));
}

static int xgbe_tx_poll(struct xgbe_channel *channel)
{
struct xgbe_prv_data *pdata = channel->pdata;
Expand Down Expand Up @@ -1171,7 +1197,6 @@ static int xgbe_rx_poll(struct xgbe_channel *channel, int budget)
{
struct xgbe_prv_data *pdata = channel->pdata;
struct xgbe_hw_if *hw_if = &pdata->hw_if;
struct xgbe_desc_if *desc_if = &pdata->desc_if;
struct xgbe_ring *ring = channel->rx_ring;
struct xgbe_ring_data *rdata;
struct xgbe_packet_data *packet;
Expand All @@ -1198,6 +1223,9 @@ static int xgbe_rx_poll(struct xgbe_channel *channel, int budget)
cur_len = 0;

read_again:
if (ring->dirty > (XGBE_RX_DESC_CNT >> 3))
xgbe_rx_refresh(channel);

rdata = XGBE_GET_DESC_DATA(ring, ring->cur);

if (hw_if->dev_read(channel))
Expand Down Expand Up @@ -1285,16 +1313,6 @@ static int xgbe_rx_poll(struct xgbe_channel *channel, int budget)
napi_gro_receive(&pdata->napi, skb);
}

if (received) {
desc_if->realloc_skb(channel);

/* Update the Rx Tail Pointer Register with address of
* the last cleaned entry */
rdata = XGBE_GET_DESC_DATA(ring, ring->rx.realloc_index - 1);
XGMAC_DMA_IOWRITE(channel, DMA_CH_RDTR_LO,
lower_32_bits(rdata->rdesc_dma));
}

DBGPR("<--xgbe_rx_poll: received = %d\n", received);

return received;
Expand All @@ -1305,21 +1323,28 @@ static int xgbe_poll(struct napi_struct *napi, int budget)
struct xgbe_prv_data *pdata = container_of(napi, struct xgbe_prv_data,
napi);
struct xgbe_channel *channel;
int processed;
int ring_budget;
int processed, last_processed;
unsigned int i;

DBGPR("-->xgbe_poll: budget=%d\n", budget);

/* Cleanup Tx ring first */
channel = pdata->channel;
for (i = 0; i < pdata->channel_count; i++, channel++)
xgbe_tx_poll(channel);

/* Process Rx ring next */
processed = 0;
channel = pdata->channel;
for (i = 0; i < pdata->channel_count; i++, channel++)
processed += xgbe_rx_poll(channel, budget - processed);
ring_budget = budget / pdata->rx_ring_count;
do {
last_processed = processed;

channel = pdata->channel;
for (i = 0; i < pdata->channel_count; i++, channel++) {
/* Cleanup Tx ring first */
xgbe_tx_poll(channel);

/* Process Rx ring next */
if (ring_budget > (budget - processed))
ring_budget = budget - processed;
processed += xgbe_rx_poll(channel, ring_budget);
}
} while ((processed < budget) && (processed != last_processed));

/* If we processed everything, we are done */
if (processed < budget) {
Expand Down
12 changes: 6 additions & 6 deletions drivers/net/ethernet/amd/xgbe/xgbe.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -146,7 +146,7 @@
#define XGBE_DMA_ARDOMAIN 0x2
#define XGBE_DMA_ARCACHE 0xb
#define XGBE_DMA_AWDOMAIN 0x2
#define XGBE_DMA_AWCACHE 0x7
#define XGBE_DMA_AWCACHE 0xf

#define XGBE_DMA_INTERRUPT_MASK 0x31c7

Expand Down Expand Up @@ -181,12 +181,12 @@


/* Default coalescing parameters */
#define XGMAC_INIT_DMA_TX_USECS 100
#define XGMAC_INIT_DMA_TX_FRAMES 16
#define XGMAC_INIT_DMA_TX_USECS 50
#define XGMAC_INIT_DMA_TX_FRAMES 25

#define XGMAC_MAX_DMA_RIWT 0xff
#define XGMAC_INIT_DMA_RX_USECS 100
#define XGMAC_INIT_DMA_RX_FRAMES 16
#define XGMAC_INIT_DMA_RX_USECS 30
#define XGMAC_INIT_DMA_RX_FRAMES 25

/* Flow control queue count */
#define XGMAC_MAX_FLOW_CONTROL_QUEUES 8
Expand Down Expand Up @@ -307,13 +307,13 @@ struct xgbe_channel {
} ____cacheline_aligned;

enum xgbe_int {
XGMAC_INT_DMA_ISR_DC0IS,
XGMAC_INT_DMA_CH_SR_TI,
XGMAC_INT_DMA_CH_SR_TPS,
XGMAC_INT_DMA_CH_SR_TBU,
XGMAC_INT_DMA_CH_SR_RI,
XGMAC_INT_DMA_CH_SR_RBU,
XGMAC_INT_DMA_CH_SR_RPS,
XGMAC_INT_DMA_CH_SR_TI_RI,
XGMAC_INT_DMA_CH_SR_FBE,
XGMAC_INT_DMA_ALL,
};
Expand Down

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