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sfc: Implement adaptive IRQ moderation

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Calculate a score for each 1000 IRQs:
- TX completions are worth 1 point
- RX completions are worth 4 if merged using LRO or 2 otherwise

Reduce moderation if the score is less than 10000, down to a minimum
of 5 us.  Increase moderation if the score is more than 20000, up to
the specified maximum.

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Ben Hutchings 2009-03-20 13:30:37 +00:00 committed by David S. Miller
parent 85451a951b
commit 6fb70fd1b5
6 changed files with 73 additions and 21 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

46
drivers/net/sfc/efx.c
View File

@ -133,6 +133,16 @@ static int phy_flash_cfg;
module_param(phy_flash_cfg, int, 0644);
MODULE_PARM_DESC(phy_flash_cfg, "Set PHYs into reflash mode initially");
static unsigned irq_adapt_low_thresh = 10000;
module_param(irq_adapt_low_thresh, uint, 0644);
MODULE_PARM_DESC(irq_adapt_low_thresh,
"Threshold score for reducing IRQ moderation");
static unsigned irq_adapt_high_thresh = 20000;
module_param(irq_adapt_high_thresh, uint, 0644);
MODULE_PARM_DESC(irq_adapt_high_thresh,
"Threshold score for increasing IRQ moderation");
/**************************************************************************
*
* Utility functions and prototypes
@ -223,6 +233,35 @@ static int efx_poll(struct napi_struct *napi, int budget)
rx_packets = efx_process_channel(channel, budget);
if (rx_packets < budget) {
struct efx_nic *efx = channel->efx;
if (channel->used_flags & EFX_USED_BY_RX &&
efx->irq_rx_adaptive &&
unlikely(++channel->irq_count == 1000)) {
unsigned old_irq_moderation = channel->irq_moderation;
if (unlikely(channel->irq_mod_score <
irq_adapt_low_thresh)) {
channel->irq_moderation =
max_t(int,
channel->irq_moderation -
FALCON_IRQ_MOD_RESOLUTION,
FALCON_IRQ_MOD_RESOLUTION);
} else if (unlikely(channel->irq_mod_score >
irq_adapt_high_thresh)) {
channel->irq_moderation =
min(channel->irq_moderation +
FALCON_IRQ_MOD_RESOLUTION,
efx->irq_rx_moderation);
}
if (channel->irq_moderation != old_irq_moderation)
falcon_set_int_moderation(channel);
channel->irq_count = 0;
channel->irq_mod_score = 0;
}
/* There is no race here; although napi_disable() will
* only wait for napi_complete(), this isn't a problem
* since efx_channel_processed() will have no effect if
@ -991,7 +1030,7 @@ static int efx_probe_nic(struct efx_nic *efx)
efx_set_channels(efx);
/* Initialise the interrupt moderation settings */
efx_init_irq_moderation(efx, tx_irq_mod_usec, rx_irq_mod_usec);
efx_init_irq_moderation(efx, tx_irq_mod_usec, rx_irq_mod_usec, true);
return 0;
}
@ -1188,7 +1227,8 @@ void efx_flush_queues(struct efx_nic *efx)
**************************************************************************/
/* Set interrupt moderation parameters */
void efx_init_irq_moderation(struct efx_nic *efx, int tx_usecs, int rx_usecs)
void efx_init_irq_moderation(struct efx_nic *efx, int tx_usecs, int rx_usecs,
bool rx_adaptive)
{
struct efx_tx_queue *tx_queue;
struct efx_rx_queue *rx_queue;
@ -1198,6 +1238,8 @@ void efx_init_irq_moderation(struct efx_nic *efx, int tx_usecs, int rx_usecs)
efx_for_each_tx_queue(tx_queue, efx)
tx_queue->channel->irq_moderation = tx_usecs;
efx->irq_rx_adaptive = rx_adaptive;
efx->irq_rx_moderation = rx_usecs;
efx_for_each_rx_queue(rx_queue, efx)
rx_queue->channel->irq_moderation = rx_usecs;
}

2
drivers/net/sfc/efx.h
View File

@ -52,7 +52,7 @@ extern void efx_schedule_reset(struct efx_nic *efx, enum reset_type type);
extern void efx_suspend(struct efx_nic *efx);
extern void efx_resume(struct efx_nic *efx);
extern void efx_init_irq_moderation(struct efx_nic *efx, int tx_usecs,
int rx_usecs);
int rx_usecs, bool rx_adaptive);
extern int efx_request_power(struct efx_nic *efx, int mw, const char *name);
extern void efx_hex_dump(const u8 *, unsigned int, const char *);

19
drivers/net/sfc/ethtool.c
View File

@ -604,7 +604,6 @@ static int efx_ethtool_get_coalesce(struct net_device *net_dev,
{
struct efx_nic *efx = netdev_priv(net_dev);
struct efx_tx_queue *tx_queue;
struct efx_rx_queue *rx_queue;
struct efx_channel *channel;
memset(coalesce, 0, sizeof(*coalesce));
@ -622,14 +621,8 @@ static int efx_ethtool_get_coalesce(struct net_device *net_dev,
}
}
/* Find lowest IRQ moderation across all used RX queues */
coalesce->rx_coalesce_usecs_irq = ~((u32) 0);
efx_for_each_rx_queue(rx_queue, efx) {
channel = rx_queue->channel;
if (channel->irq_moderation < coalesce->rx_coalesce_usecs_irq)
coalesce->rx_coalesce_usecs_irq =
channel->irq_moderation;
}
coalesce->use_adaptive_rx_coalesce = efx->irq_rx_adaptive;
coalesce->rx_coalesce_usecs_irq = efx->irq_rx_moderation;
return 0;
}
@ -643,10 +636,9 @@ static int efx_ethtool_set_coalesce(struct net_device *net_dev,
struct efx_nic *efx = netdev_priv(net_dev);
struct efx_channel *channel;
struct efx_tx_queue *tx_queue;
unsigned tx_usecs, rx_usecs;
unsigned tx_usecs, rx_usecs, adaptive;
if (coalesce->use_adaptive_rx_coalesce ||
coalesce->use_adaptive_tx_coalesce)
if (coalesce->use_adaptive_tx_coalesce)
return -EOPNOTSUPP;
if (coalesce->rx_coalesce_usecs || coalesce->tx_coalesce_usecs) {
@ -657,6 +649,7 @@ static int efx_ethtool_set_coalesce(struct net_device *net_dev,
rx_usecs = coalesce->rx_coalesce_usecs_irq;
tx_usecs = coalesce->tx_coalesce_usecs_irq;
adaptive = coalesce->use_adaptive_rx_coalesce;
/* If the channel is shared only allow RX parameters to be set */
efx_for_each_tx_queue(tx_queue, efx) {
@ -668,7 +661,7 @@ static int efx_ethtool_set_coalesce(struct net_device *net_dev,
}
}
efx_init_irq_moderation(efx, tx_usecs, rx_usecs);
efx_init_irq_moderation(efx, tx_usecs, rx_usecs, adaptive);
/* Reset channel to pick up new moderation value. Note that
* this may change the value of the irq_moderation field

16
drivers/net/sfc/falcon.c
View File

@ -729,6 +729,9 @@ static void falcon_handle_tx_event(struct efx_channel *channel,
tx_ev_desc_ptr = EFX_QWORD_FIELD(*event, TX_EV_DESC_PTR);
tx_ev_q_label = EFX_QWORD_FIELD(*event, TX_EV_Q_LABEL);
tx_queue = &efx->tx_queue[tx_ev_q_label];
channel->irq_mod_score +=
(tx_ev_desc_ptr - tx_queue->read_count) &
efx->type->txd_ring_mask;
efx_xmit_done(tx_queue, tx_ev_desc_ptr);
} else if (EFX_QWORD_FIELD(*event, TX_EV_WQ_FF_FULL)) {
/* Rewrite the FIFO write pointer */
@ -898,6 +901,8 @@ static void falcon_handle_rx_event(struct efx_channel *channel,
discard = true;
}
channel->irq_mod_score += 2;
/* Handle received packet */
efx_rx_packet(rx_queue, rx_ev_desc_ptr, rx_ev_byte_cnt,
checksummed, discard);
@ -1075,14 +1080,15 @@ void falcon_set_int_moderation(struct efx_channel *channel)
* program is based at 0. So actual interrupt moderation
* achieved is ((x + 1) * res).
*/
unsigned int res = 5;
channel->irq_moderation -= (channel->irq_moderation % res);
if (channel->irq_moderation < res)
channel->irq_moderation = res;
channel->irq_moderation -= (channel->irq_moderation %
FALCON_IRQ_MOD_RESOLUTION);
if (channel->irq_moderation < FALCON_IRQ_MOD_RESOLUTION)
channel->irq_moderation = FALCON_IRQ_MOD_RESOLUTION;
EFX_POPULATE_DWORD_2(timer_cmd,
TIMER_MODE, TIMER_MODE_INT_HLDOFF,
TIMER_VAL,
(channel->irq_moderation / res) - 1);
channel->irq_moderation /
FALCON_IRQ_MOD_RESOLUTION - 1);
} else {
EFX_POPULATE_DWORD_2(timer_cmd,
TIMER_MODE, TIMER_MODE_DIS,

2
drivers/net/sfc/falcon.h
View File

@ -85,6 +85,8 @@ extern void falcon_set_int_moderation(struct efx_channel *channel);
extern void falcon_disable_interrupts(struct efx_nic *efx);
extern void falcon_fini_interrupt(struct efx_nic *efx);
#define FALCON_IRQ_MOD_RESOLUTION 5
/* Global Resources */
extern int falcon_probe_nic(struct efx_nic *efx);
extern int falcon_probe_resources(struct efx_nic *efx);

9
drivers/net/sfc/net_driver.h
View File

@ -336,6 +336,8 @@ enum efx_rx_alloc_method {
* @eventq_read_ptr: Event queue read pointer
* @last_eventq_read_ptr: Last event queue read pointer value.
* @eventq_magic: Event queue magic value for driver-generated test events
* @irq_count: Number of IRQs since last adaptive moderation decision
* @irq_mod_score: IRQ moderation score
* @rx_alloc_level: Watermark based heuristic counter for pushing descriptors
* and diagnostic counters
* @rx_alloc_push_pages: RX allocation method currently in use for pushing
@ -364,6 +366,9 @@ struct efx_channel {
unsigned int last_eventq_read_ptr;
unsigned int eventq_magic;
unsigned int irq_count;
unsigned int irq_mod_score;
int rx_alloc_level;
int rx_alloc_push_pages;
@ -703,6 +708,8 @@ union efx_multicast_hash {
* @membase: Memory BAR value
* @biu_lock: BIU (bus interface unit) lock
* @interrupt_mode: Interrupt mode
* @irq_rx_adaptive: Adaptive IRQ moderation enabled for RX event queues
* @irq_rx_moderation: IRQ moderation time for RX event queues
* @i2c_adap: I2C adapter
* @board_info: Board-level information
* @state: Device state flag. Serialised by the rtnl_lock.
@ -784,6 +791,8 @@ struct efx_nic {
void __iomem *membase;
spinlock_t biu_lock;
enum efx_int_mode interrupt_mode;
bool irq_rx_adaptive;
unsigned int irq_rx_moderation;
struct i2c_adapter i2c_adap;
struct efx_board board_info;