Commit 6fb70fd1 authored by Ben Hutchings's avatar Ben Hutchings Committed by David S. Miller
Browse files

sfc: Implement adaptive IRQ moderation 



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: default avatarBen Hutchings <bhutchings@solarflare.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 85451a95

drivers/net/sfc/efx.c

+44 −2
Original line number Diff line number Diff line
@@ -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;

}

drivers/net/sfc/efx.h

+1 −1
Original line number Diff line number Diff line
@@ -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 *);

drivers/net/sfc/ethtool.c

+6 −13
Original line number Diff line number Diff line
@@ -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

drivers/net/sfc/falcon.c

+11 −5
Original line number Diff line number Diff line
@@ -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,

drivers/net/sfc/falcon.h

+2 −0
Original line number Diff line number Diff line
@@ -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);