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Commit 8a9ca110 authored by Alexander Duyck's avatar Alexander Duyck Committed by Jeff Kirsher
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ixgbevf: Limit lowest interrupt rate for adaptive interrupt moderation to 12K 



This patch is the ixgbevf version of commit 8ac34f10 "ixgbe: Limit
lowest interrupt rate for adaptive interrupt moderation to 12K"

The same logic applies here as well as the same results since a netperf
test will starve for memory in the time from one Tx interrupt to the next.
As a result the ixgbevf driver underperformed when compared to vhost_net.

Signed-off-by: default avatarAlexander Duyck <aduyck@mirantis.com>
Tested-by: default avatarDarin Miller <darin.j.miller@intel.com>
Signed-off-by: default avatarJeff Kirsher <jeffrey.t.kirsher@intel.com>
parent d91e3a7d

drivers/net/ethernet/intel/ixgbevf/ethtool.c

+1 −1
Original line number Diff line number Diff line
@@ -774,7 +774,7 @@ static int ixgbevf_set_coalesce(struct net_device *netdev, 
		adapter->tx_itr_setting = ec->tx_coalesce_usecs;



	if (adapter->tx_itr_setting == 1)

		tx_itr_param = IXGBE_10K_ITR;

		tx_itr_param = IXGBE_12K_ITR;

	else

		tx_itr_param = adapter->tx_itr_setting;

drivers/net/ethernet/intel/ixgbevf/ixgbevf.h

+1 −2
Original line number Diff line number Diff line
@@ -326,8 +326,7 @@ static inline bool ixgbevf_qv_disable(struct ixgbevf_q_vector *q_vector) 
#define IXGBE_MIN_RSC_ITR	24

#define IXGBE_100K_ITR		40

#define IXGBE_20K_ITR		200

#define IXGBE_10K_ITR		400

#define IXGBE_8K_ITR		500

#define IXGBE_12K_ITR		336



/* Helper macros to switch between ints/sec and what the register uses.

 * And yes, it's the same math going both ways.  The lowest value

drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c

+3 −3
Original line number Diff line number Diff line
@@ -1138,7 +1138,7 @@ static void ixgbevf_configure_msix(struct ixgbevf_adapter *adapter) 
		if (q_vector->tx.ring && !q_vector->rx.ring) {

			/* Tx only vector */

			if (adapter->tx_itr_setting == 1)

				q_vector->itr = IXGBE_10K_ITR;

				q_vector->itr = IXGBE_12K_ITR;

			else

				q_vector->itr = adapter->tx_itr_setting;

		} else {
@@ -1196,7 +1196,7 @@ static void ixgbevf_update_itr(struct ixgbevf_q_vector *q_vector, 
	/* simple throttle rate management

	 *    0-20MB/s lowest (100000 ints/s)

	 *   20-100MB/s low   (20000 ints/s)

	 *  100-1249MB/s bulk (8000 ints/s)

	 *  100-1249MB/s bulk (12000 ints/s)

	 */

	/* what was last interrupt timeslice? */

	timepassed_us = q_vector->itr >> 2;
@@ -1247,7 +1247,7 @@ static void ixgbevf_set_itr(struct ixgbevf_q_vector *q_vector) 
		break;

	case bulk_latency:

	default:

		new_itr = IXGBE_8K_ITR;

		new_itr = IXGBE_12K_ITR;

		break;

	}