From 3ebe8fdeb043e8c630cac6dc90d483e729e17017 Mon Sep 17 00:00:00 2001 From: Alexander Duyck Date: Wed, 25 Apr 2012 04:36:38 +0000 Subject: [PATCH] ixgbe: Set Drop_EN bit when multiple Rx queues are present w/o flow control The drop enable bit can be used to improve the performance of the adapter in the case of multiple queues being present. This performance gain is due to the fact that some slower CPUs can cause the FIFO to backfill preventing faster CPUs from receiving additional work. By setting the drop enable bit we prevent this and instead just drop the packets that would have been bound for the slower CPU. Signed-off-by: Alexander Duyck Tested-by: Ross Brattain Signed-off-by: Jeff Kirsher --- drivers/net/ethernet/intel/ixgbe/ixgbe.h | 1 + .../net/ethernet/intel/ixgbe/ixgbe_dcb_nl.c | 5 ++ drivers/net/ethernet/intel/ixgbe/ixgbe_main.c | 59 ++++++++++++++++++- 3 files changed, 64 insertions(+), 1 deletion(-) diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe.h b/drivers/net/ethernet/intel/ixgbe/ixgbe.h index 425f86432f90..2262bf715b56 100644 --- a/drivers/net/ethernet/intel/ixgbe/ixgbe.h +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe.h @@ -652,6 +652,7 @@ extern void ixgbe_atr_compute_perfect_hash_82599(union ixgbe_atr_input *input, union ixgbe_atr_input *mask); extern void ixgbe_set_rx_mode(struct net_device *netdev); #ifdef CONFIG_IXGBE_DCB +extern void ixgbe_set_rx_drop_en(struct ixgbe_adapter *adapter); extern int ixgbe_setup_tc(struct net_device *dev, u8 tc); #endif extern void ixgbe_tx_ctxtdesc(struct ixgbe_ring *, u32, u32, u32, u32); diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_dcb_nl.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_dcb_nl.c index 7f2fa6992775..5164a21b13ca 100644 --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_dcb_nl.c +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_dcb_nl.c @@ -395,6 +395,9 @@ static u8 ixgbe_dcbnl_set_all(struct net_device *netdev) } else { hw->mac.ops.fc_enable(hw); } + + ixgbe_set_rx_drop_en(adapter); + ret = DCB_HW_CHG; } @@ -641,6 +644,8 @@ static int ixgbe_dcbnl_ieee_setpfc(struct net_device *dev, else err = hw->mac.ops.fc_enable(hw); + ixgbe_set_rx_drop_en(adapter); + return err; } diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c index 0915e77cf375..1693ec3d4046 100644 --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c @@ -2771,6 +2771,61 @@ static void ixgbe_configure_tx(struct ixgbe_adapter *adapter) ixgbe_configure_tx_ring(adapter, adapter->tx_ring[i]); } +static void ixgbe_enable_rx_drop(struct ixgbe_adapter *adapter, + struct ixgbe_ring *ring) +{ + struct ixgbe_hw *hw = &adapter->hw; + u8 reg_idx = ring->reg_idx; + u32 srrctl = IXGBE_READ_REG(hw, IXGBE_SRRCTL(reg_idx)); + + srrctl |= IXGBE_SRRCTL_DROP_EN; + + IXGBE_WRITE_REG(hw, IXGBE_SRRCTL(reg_idx), srrctl); +} + +static void ixgbe_disable_rx_drop(struct ixgbe_adapter *adapter, + struct ixgbe_ring *ring) +{ + struct ixgbe_hw *hw = &adapter->hw; + u8 reg_idx = ring->reg_idx; + u32 srrctl = IXGBE_READ_REG(hw, IXGBE_SRRCTL(reg_idx)); + + srrctl &= ~IXGBE_SRRCTL_DROP_EN; + + IXGBE_WRITE_REG(hw, IXGBE_SRRCTL(reg_idx), srrctl); +} + +#ifdef CONFIG_IXGBE_DCB +void ixgbe_set_rx_drop_en(struct ixgbe_adapter *adapter) +#else +static void ixgbe_set_rx_drop_en(struct ixgbe_adapter *adapter) +#endif +{ + int i; + bool pfc_en = adapter->dcb_cfg.pfc_mode_enable; + + if (adapter->ixgbe_ieee_pfc) + pfc_en |= !!(adapter->ixgbe_ieee_pfc->pfc_en); + + /* + * We should set the drop enable bit if: + * SR-IOV is enabled + * or + * Number of Rx queues > 1 and flow control is disabled + * + * This allows us to avoid head of line blocking for security + * and performance reasons. + */ + if (adapter->num_vfs || (adapter->num_rx_queues > 1 && + !(adapter->hw.fc.current_mode & ixgbe_fc_tx_pause) && !pfc_en)) { + for (i = 0; i < adapter->num_rx_queues; i++) + ixgbe_enable_rx_drop(adapter, adapter->rx_ring[i]); + } else { + for (i = 0; i < adapter->num_rx_queues; i++) + ixgbe_disable_rx_drop(adapter, adapter->rx_ring[i]); + } +} + #define IXGBE_SRRCTL_BSIZEHDRSIZE_SHIFT 2 static void ixgbe_configure_srrctl(struct ixgbe_adapter *adapter, @@ -5276,8 +5331,10 @@ static void ixgbe_watchdog_update_link(struct ixgbe_adapter *adapter) if (adapter->ixgbe_ieee_pfc) pfc_en |= !!(adapter->ixgbe_ieee_pfc->pfc_en); - if (link_up && !((adapter->flags & IXGBE_FLAG_DCB_ENABLED) && pfc_en)) + if (link_up && !((adapter->flags & IXGBE_FLAG_DCB_ENABLED) && pfc_en)) { hw->mac.ops.fc_enable(hw); + ixgbe_set_rx_drop_en(adapter); + } if (link_up || time_after(jiffies, (adapter->link_check_timeout + -- 2.20.1