Commit 4bb7f4cf authored by Arthur Kiyanovski's avatar Arthur Kiyanovski Committed by David S. Miller
Browse files

net: ena: reduce driver load time 



This commit reduces the driver load time by using usec resolution
instead of msec when polling for hardware state change.

Also add back-off mechanism to handle cases where minimal sleep
time is not enough.

Signed-off-by: default avatarJosh Triplett <josh@joshtriplett.org>
Signed-off-by: default avatarSameeh Jubran <sameehj@amazon.com>
Signed-off-by: default avatarArthur Kiyanovski <akiyano@amazon.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent b0ae3ac4

drivers/net/ethernet/amazon/ena/ena_com.c

+26 −10
Original line number Diff line number Diff line
@@ -62,7 +62,9 @@ 


#define ENA_REGS_ADMIN_INTR_MASK 1



#define ENA_POLL_MS	5

#define ENA_MIN_ADMIN_POLL_US 100



#define ENA_MAX_ADMIN_POLL_US 5000



/*****************************************************************************/

/*****************************************************************************/
@@ -540,12 +542,20 @@ static int ena_com_comp_status_to_errno(u8 comp_status) 
	return -EINVAL;

}



static void ena_delay_exponential_backoff_us(u32 exp, u32 delay_us)

{

	delay_us = max_t(u32, ENA_MIN_ADMIN_POLL_US, delay_us);

	delay_us = min_t(u32, delay_us * (1U << exp), ENA_MAX_ADMIN_POLL_US);

	usleep_range(delay_us, 2 * delay_us);

}



static int ena_com_wait_and_process_admin_cq_polling(struct ena_comp_ctx *comp_ctx,

						     struct ena_com_admin_queue *admin_queue)

{

	unsigned long flags = 0;

	unsigned long timeout;

	int ret;

	u32 exp = 0;



	timeout = jiffies + usecs_to_jiffies(admin_queue->completion_timeout);
@@ -569,7 +579,8 @@ static int ena_com_wait_and_process_admin_cq_polling(struct ena_comp_ctx *comp_c 
			goto err;

		}



		msleep(ENA_POLL_MS);

		ena_delay_exponential_backoff_us(exp++,

						 admin_queue->ena_dev->ena_min_poll_delay_us);

	}



	if (unlikely(comp_ctx->status == ENA_CMD_ABORTED)) {
@@ -939,12 +950,13 @@ static void ena_com_io_queue_free(struct ena_com_dev *ena_dev, 
static int wait_for_reset_state(struct ena_com_dev *ena_dev, u32 timeout,

				u16 exp_state)

{

	u32 val, i;

	u32 val, exp = 0;

	unsigned long timeout_stamp;



	/* Convert timeout from resolution of 100ms to ENA_POLL_MS */

	timeout = (timeout * 100) / ENA_POLL_MS;

	/* Convert timeout from resolution of 100ms to us resolution. */

	timeout_stamp = jiffies + usecs_to_jiffies(100 * 1000 * timeout);



	for (i = 0; i < timeout; i++) {

	while (1) {

		val = ena_com_reg_bar_read32(ena_dev, ENA_REGS_DEV_STS_OFF);



		if (unlikely(val == ENA_MMIO_READ_TIMEOUT)) {
@@ -956,10 +968,11 @@ static int wait_for_reset_state(struct ena_com_dev *ena_dev, u32 timeout, 
			exp_state)

			return 0;



		msleep(ENA_POLL_MS);

	}



		if (time_is_before_jiffies(timeout_stamp))

			return -ETIME;



		ena_delay_exponential_backoff_us(exp++, ena_dev->ena_min_poll_delay_us);

	}

}



static bool ena_com_check_supported_feature_id(struct ena_com_dev *ena_dev,
@@ -1436,11 +1449,13 @@ void ena_com_wait_for_abort_completion(struct ena_com_dev *ena_dev) 
{

	struct ena_com_admin_queue *admin_queue = &ena_dev->admin_queue;

	unsigned long flags = 0;

	u32 exp = 0;



	spin_lock_irqsave(&admin_queue->q_lock, flags);

	while (atomic_read(&admin_queue->outstanding_cmds) != 0) {

		spin_unlock_irqrestore(&admin_queue->q_lock, flags);

		msleep(ENA_POLL_MS);

		ena_delay_exponential_backoff_us(exp++,

						 ena_dev->ena_min_poll_delay_us);

		spin_lock_irqsave(&admin_queue->q_lock, flags);

	}

	spin_unlock_irqrestore(&admin_queue->q_lock, flags);
@@ -1788,6 +1803,7 @@ int ena_com_admin_init(struct ena_com_dev *ena_dev, 
	if (ret)

		goto error;



	admin_queue->ena_dev = ena_dev;

	admin_queue->running_state = true;



	return 0;

drivers/net/ethernet/amazon/ena/ena_com.h

+3 −0
Original line number Diff line number Diff line
@@ -239,6 +239,7 @@ struct ena_com_stats_admin { 


struct ena_com_admin_queue {

	void *q_dmadev;

	struct ena_com_dev *ena_dev;

	spinlock_t q_lock; /* spinlock for the admin queue */



	struct ena_comp_ctx *comp_ctx;
@@ -351,6 +352,8 @@ struct ena_com_dev { 
	struct ena_intr_moder_entry *intr_moder_tbl;



	struct ena_com_llq_info llq_info;



	u32 ena_min_poll_delay_us;

};



struct ena_com_dev_get_features_ctx {

drivers/net/ethernet/amazon/ena/ena_netdev.c

+2 −0
Original line number Diff line number Diff line
@@ -4166,6 +4166,8 @@ static int ena_probe(struct pci_dev *pdev, const struct pci_device_id *ent) 
		goto err_free_region;

	}



	ena_dev->ena_min_poll_delay_us = ENA_ADMIN_POLL_DELAY_US;



	ena_dev->dmadev = &pdev->dev;



	rc = ena_device_init(ena_dev, pdev, &get_feat_ctx, &wd_state);

drivers/net/ethernet/amazon/ena/ena_netdev.h

+2 −0
Original line number Diff line number Diff line
@@ -129,6 +129,8 @@ 
#define ENA_IO_IRQ_FIRST_IDX		1

#define ENA_IO_IRQ_IDX(q)		(ENA_IO_IRQ_FIRST_IDX + (q))



#define ENA_ADMIN_POLL_DELAY_US 100



/* ENA device should send keep alive msg every 1 sec.

 * We wait for 6 sec just to be on the safe side.

 */

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