From 9c6f222fd4e8863d4cc0e915d8c6363354043e66 Mon Sep 17 00:00:00 2001 From: Nicholas Nunley Date: Tue, 5 Nov 2019 04:22:14 -0800 Subject: [PATCH] iavf: initialize ITRN registers with correct values Since commit 62ecce5b1075 ("i40e/i40evf: Use usec value instead of reg value for ITR defines") the driver tracks the interrupt throttling intervals in single usec units, although the actual ITRN registers are programmed in 2 usec units. Most register programming flows in the driver correctly handle the conversion, although it is currently not applied when the registers are initialized to their default values. Most of the time this doesn't present a problem since the default values are usually immediately overwritten through the standard adaptive throttling mechanism, or updated manually by the user, but if adaptive throttling is disabled and the interval values are left alone then the incorrect value will persist. Since the intended default interval of 50 usecs (vs. 100 usecs as programmed) performs better for most traffic workloads, this can lead to performance regressions. This patch adds the correct conversion when writing the initial values to the ITRN registers. Signed-off-by: Nicholas Nunley Tested-by: Andrew Bowers Signed-off-by: Jeff Kirsher --- drivers/net/ethernet/intel/iavf/iavf_main.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/net/ethernet/intel/iavf/iavf_main.c b/drivers/net/ethernet/intel/iavf/iavf_main.c index 8f310e520b069..821987da5698a 100644 --- a/drivers/net/ethernet/intel/iavf/iavf_main.c +++ b/drivers/net/ethernet/intel/iavf/iavf_main.c @@ -314,7 +314,7 @@ iavf_map_vector_to_rxq(struct iavf_adapter *adapter, int v_idx, int r_idx) q_vector->rx.target_itr = ITR_TO_REG(rx_ring->itr_setting); q_vector->ring_mask |= BIT(r_idx); wr32(hw, IAVF_VFINT_ITRN1(IAVF_RX_ITR, q_vector->reg_idx), - q_vector->rx.current_itr); + q_vector->rx.current_itr >> 1); q_vector->rx.current_itr = q_vector->rx.target_itr; } @@ -340,7 +340,7 @@ iavf_map_vector_to_txq(struct iavf_adapter *adapter, int v_idx, int t_idx) q_vector->tx.target_itr = ITR_TO_REG(tx_ring->itr_setting); q_vector->num_ringpairs++; wr32(hw, IAVF_VFINT_ITRN1(IAVF_TX_ITR, q_vector->reg_idx), - q_vector->tx.target_itr); + q_vector->tx.target_itr >> 1); q_vector->tx.current_itr = q_vector->tx.target_itr; } -- 2.39.5