From c29af37fd5b7b649b57139cee6bf730c996fe756 Mon Sep 17 00:00:00 2001 From: Anjali Singhai Jain Date: Sat, 10 Jan 2015 01:07:19 +0000 Subject: [PATCH] i40evf: Force Tx writeback on ITR This patch forces Tx descriptor writebacks on ITR by kicking off the SWINT interrupt when we notice that there are non-cache-aligned Tx descriptors waiting in the ring while interrupts are disabled under NAPI. Change-ID: dd6d9675629bf266c7515ad7a201394618c35444 Signed-off-by: Anjali Singhai Jain Signed-off-by: Jeff Kirsher --- drivers/net/ethernet/intel/i40e/i40e_txrx.c | 4 +-- drivers/net/ethernet/intel/i40evf/i40e_txrx.c | 38 +++++++++++++++++++++++++-- drivers/net/ethernet/intel/i40evf/i40e_txrx.h | 1 + 3 files changed, 39 insertions(+), 4 deletions(-) diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.c b/drivers/net/ethernet/intel/i40e/i40e_txrx.c index 420d662..5aa6ef1 100644 --- a/drivers/net/ethernet/intel/i40e/i40e_txrx.c +++ b/drivers/net/ethernet/intel/i40e/i40e_txrx.c @@ -836,8 +836,8 @@ static void i40e_force_wb(struct i40e_vsi *vsi, struct i40e_q_vector *q_vector) { u32 val = I40E_PFINT_DYN_CTLN_INTENA_MASK | I40E_PFINT_DYN_CTLN_SWINT_TRIG_MASK | - I40E_PFINT_DYN_CTLN_SW_ITR_INDX_ENA_MASK - /* allow 00 to be written to the index */; + I40E_PFINT_DYN_CTLN_SW_ITR_INDX_ENA_MASK; + /* allow 00 to be written to the index */ wr32(&vsi->back->hw, I40E_PFINT_DYN_CTLN(q_vector->v_idx + vsi->base_vector - 1), diff --git a/drivers/net/ethernet/intel/i40evf/i40e_txrx.c b/drivers/net/ethernet/intel/i40evf/i40e_txrx.c index 82c3798..4bf15da 100644 --- a/drivers/net/ethernet/intel/i40evf/i40e_txrx.c +++ b/drivers/net/ethernet/intel/i40evf/i40e_txrx.c @@ -192,6 +192,8 @@ static inline u32 i40e_get_head(struct i40e_ring *tx_ring) return le32_to_cpu(*(volatile __le32 *)head); } +#define WB_STRIDE 0x3 + /** * i40e_clean_tx_irq - Reclaim resources after transmit completes * @tx_ring: tx ring to clean @@ -293,6 +295,14 @@ static bool i40e_clean_tx_irq(struct i40e_ring *tx_ring, int budget) tx_ring->q_vector->tx.total_bytes += total_bytes; tx_ring->q_vector->tx.total_packets += total_packets; + if (budget && + !((i & WB_STRIDE) == WB_STRIDE) && + !test_bit(__I40E_DOWN, &tx_ring->vsi->state) && + (I40E_DESC_UNUSED(tx_ring) != tx_ring->count)) + tx_ring->arm_wb = true; + else + tx_ring->arm_wb = false; + if (check_for_tx_hang(tx_ring) && i40e_check_tx_hang(tx_ring)) { /* schedule immediate reset if we believe we hung */ dev_info(tx_ring->dev, "Detected Tx Unit Hang\n" @@ -344,6 +354,24 @@ static bool i40e_clean_tx_irq(struct i40e_ring *tx_ring, int budget) } /** + * i40e_force_wb -Arm hardware to do a wb on noncache aligned descriptors + * @vsi: the VSI we care about + * @q_vector: the vector on which to force writeback + * + **/ +static void i40e_force_wb(struct i40e_vsi *vsi, struct i40e_q_vector *q_vector) +{ + u32 val = I40E_VFINT_DYN_CTLN_INTENA_MASK | + I40E_VFINT_DYN_CTLN_SWINT_TRIG_MASK | + I40E_VFINT_DYN_CTLN_SW_ITR_INDX_ENA_MASK; + /* allow 00 to be written to the index */ + + wr32(&vsi->back->hw, + I40E_VFINT_DYN_CTLN1(q_vector->v_idx + vsi->base_vector - 1), + val); +} + +/** * i40e_set_new_dynamic_itr - Find new ITR level * @rc: structure containing ring performance data * @@ -1065,6 +1093,7 @@ int i40evf_napi_poll(struct napi_struct *napi, int budget) struct i40e_vsi *vsi = q_vector->vsi; struct i40e_ring *ring; bool clean_complete = true; + bool arm_wb = false; int budget_per_ring; if (test_bit(__I40E_DOWN, &vsi->state)) { @@ -1075,8 +1104,10 @@ int i40evf_napi_poll(struct napi_struct *napi, int budget) /* Since the actual Tx work is minimal, we can give the Tx a larger * budget and be more aggressive about cleaning up the Tx descriptors. */ - i40e_for_each_ring(ring, q_vector->tx) + i40e_for_each_ring(ring, q_vector->tx) { clean_complete &= i40e_clean_tx_irq(ring, vsi->work_limit); + arm_wb |= ring->arm_wb; + } /* We attempt to distribute budget to each Rx queue fairly, but don't * allow the budget to go below 1 because that would exit polling early. @@ -1087,8 +1118,11 @@ int i40evf_napi_poll(struct napi_struct *napi, int budget) clean_complete &= i40e_clean_rx_irq(ring, budget_per_ring); /* If work not completed, return budget and polling will return */ - if (!clean_complete) + if (!clean_complete) { + if (arm_wb) + i40e_force_wb(vsi, q_vector); return budget; + } /* Work is done so exit the polling mode and re-enable the interrupt */ napi_complete(napi); diff --git a/drivers/net/ethernet/intel/i40evf/i40e_txrx.h b/drivers/net/ethernet/intel/i40evf/i40e_txrx.h index c7f2962..4e15903 100644 --- a/drivers/net/ethernet/intel/i40evf/i40e_txrx.h +++ b/drivers/net/ethernet/intel/i40evf/i40e_txrx.h @@ -238,6 +238,7 @@ struct i40e_ring { u8 atr_count; bool ring_active; /* is ring online or not */ + bool arm_wb; /* do something to arm write back */ /* stats structs */ struct i40e_queue_stats stats; -- 2.7.4