i40e/i40evf: Fix and refactor dynamic ITR code

This patch changes the switch statement for dynamic interrupt throttling
and adds a default case. With this patch, we check the latency setting
instead of the current ITR settings and the included refactor improves
performance.

Without this patch, the ITR setting would never change dynamically, and
there was no default.

Change-ID: Idb5a8a14c7109ec47c90f6e94bd43baa17d7ee37
Signed-off-by: Carolyn Wyborny <carolyn.wyborny@intel.com>
Signed-off-by: Anjali Singhai Jain <anjali.singhai@intel.com>
Tested-by: Jim Young <james.m.young@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/i40e/i40e_txrx.c

@@ -892,7 +892,7 @@ static void i40e_set_new_dynamic_itr(struct i40e_ring_container *rc)
 	 *  20-1249MB/s bulk   (8000 ints/s)
 	 */
 	bytes_per_int = rc->total_bytes / rc->itr;
-	switch (rc->itr) {
+	switch (new_latency_range) {
 	case I40E_LOWEST_LATENCY:
 		if (bytes_per_int > 10)
 			new_latency_range = I40E_LOW_LATENCY;
@@ -905,9 +905,14 @@ static void i40e_set_new_dynamic_itr(struct i40e_ring_container *rc)
 		break;
 	case I40E_BULK_LATENCY:
 		if (bytes_per_int <= 20)
-			rc->latency_range = I40E_LOW_LATENCY;
+			new_latency_range = I40E_LOW_LATENCY;
+		break;
+	default:
+		if (bytes_per_int <= 20)
+			new_latency_range = I40E_LOW_LATENCY;
 		break;
 	}
+	rc->latency_range = new_latency_range;
 
 	switch (new_latency_range) {
 	case I40E_LOWEST_LATENCY:
@@ -923,41 +928,13 @@ static void i40e_set_new_dynamic_itr(struct i40e_ring_container *rc)
 		break;
 	}
 
-	if (new_itr != rc->itr) {
-		/* do an exponential smoothing */
-		new_itr = (10 * new_itr * rc->itr) /
-			  ((9 * new_itr) + rc->itr);
-		rc->itr = new_itr & I40E_MAX_ITR;
-	}
+	if (new_itr != rc->itr)
+		rc->itr = new_itr;
 
 	rc->total_bytes = 0;
 	rc->total_packets = 0;
 }
 
-/**
- * i40e_update_dynamic_itr - Adjust ITR based on bytes per int
- * @q_vector: the vector to adjust
- **/
-static void i40e_update_dynamic_itr(struct i40e_q_vector *q_vector)
-{
-	u16 vector = q_vector->vsi->base_vector + q_vector->v_idx;
-	struct i40e_hw *hw = &q_vector->vsi->back->hw;
-	u32 reg_addr;
-	u16 old_itr;
-
-	reg_addr = I40E_PFINT_ITRN(I40E_RX_ITR, vector - 1);
-	old_itr = q_vector->rx.itr;
-	i40e_set_new_dynamic_itr(&q_vector->rx);
-	if (old_itr != q_vector->rx.itr)
-		wr32(hw, reg_addr, q_vector->rx.itr);
-
-	reg_addr = I40E_PFINT_ITRN(I40E_TX_ITR, vector - 1);
-	old_itr = q_vector->tx.itr;
-	i40e_set_new_dynamic_itr(&q_vector->tx);
-	if (old_itr != q_vector->tx.itr)
-		wr32(hw, reg_addr, q_vector->tx.itr);
-}
-
 /**
  * i40e_clean_programming_status - clean the programming status descriptor
  * @rx_ring: the rx ring that has this descriptor
@@ -1826,6 +1803,68 @@ static int i40e_clean_rx_irq_1buf(struct i40e_ring *rx_ring, int budget)
 	return total_rx_packets;
 }
 
+/**
+ * i40e_update_enable_itr - Update itr and re-enable MSIX interrupt
+ * @vsi: the VSI we care about
+ * @q_vector: q_vector for which itr is being updated and interrupt enabled
+ *
+ **/
+static inline void i40e_update_enable_itr(struct i40e_vsi *vsi,
+					  struct i40e_q_vector *q_vector)
+{
+	struct i40e_hw *hw = &vsi->back->hw;
+	u16 old_itr;
+	int vector;
+	u32 val;
+
+	vector = (q_vector->v_idx + vsi->base_vector);
+	if (ITR_IS_DYNAMIC(vsi->rx_itr_setting)) {
+		old_itr = q_vector->rx.itr;
+		i40e_set_new_dynamic_itr(&q_vector->rx);
+		if (old_itr != q_vector->rx.itr) {
+			val = I40E_PFINT_DYN_CTLN_INTENA_MASK |
+			I40E_PFINT_DYN_CTLN_CLEARPBA_MASK |
+			(I40E_RX_ITR <<
+				I40E_PFINT_DYN_CTLN_ITR_INDX_SHIFT) |
+			(q_vector->rx.itr <<
+				I40E_PFINT_DYN_CTLN_INTERVAL_SHIFT);
+		} else {
+			val = I40E_PFINT_DYN_CTLN_INTENA_MASK |
+			I40E_PFINT_DYN_CTLN_CLEARPBA_MASK |
+			(I40E_ITR_NONE <<
+				I40E_PFINT_DYN_CTLN_ITR_INDX_SHIFT);
+		}
+		if (!test_bit(__I40E_DOWN, &vsi->state))
+			wr32(hw, I40E_PFINT_DYN_CTLN(vector - 1), val);
+	} else {
+		i40e_irq_dynamic_enable(vsi,
+					q_vector->v_idx + vsi->base_vector);
+	}
+	if (ITR_IS_DYNAMIC(vsi->tx_itr_setting)) {
+		old_itr = q_vector->tx.itr;
+		i40e_set_new_dynamic_itr(&q_vector->tx);
+		if (old_itr != q_vector->tx.itr) {
+			val = I40E_PFINT_DYN_CTLN_INTENA_MASK |
+				I40E_PFINT_DYN_CTLN_CLEARPBA_MASK |
+				(I40E_TX_ITR <<
+				   I40E_PFINT_DYN_CTLN_ITR_INDX_SHIFT) |
+				(q_vector->tx.itr <<
+				   I40E_PFINT_DYN_CTLN_INTERVAL_SHIFT);
+		} else {
+			val = I40E_PFINT_DYN_CTLN_INTENA_MASK |
+				I40E_PFINT_DYN_CTLN_CLEARPBA_MASK |
+				(I40E_ITR_NONE <<
+				   I40E_PFINT_DYN_CTLN_ITR_INDX_SHIFT);
+		}
+		if (!test_bit(__I40E_DOWN, &vsi->state))
+			wr32(hw, I40E_PFINT_DYN_CTLN(q_vector->v_idx +
+			      vsi->base_vector - 1), val);
+	} else {
+		i40e_irq_dynamic_enable(vsi,
+					q_vector->v_idx + vsi->base_vector);
+	}
+}
+
 /**
  * i40e_napi_poll - NAPI polling Rx/Tx cleanup routine
  * @napi: napi struct with our devices info in it
@@ -1882,33 +1921,24 @@ int i40e_napi_poll(struct napi_struct *napi, int budget)
 
 	/* Work is done so exit the polling mode and re-enable the interrupt */
 	napi_complete(napi);
-	if (ITR_IS_DYNAMIC(vsi->rx_itr_setting) ||
-	    ITR_IS_DYNAMIC(vsi->tx_itr_setting))
-		i40e_update_dynamic_itr(q_vector);
-
-	if (!test_bit(__I40E_DOWN, &vsi->state)) {
 	if (vsi->back->flags & I40E_FLAG_MSIX_ENABLED) {
-			i40e_irq_dynamic_enable(vsi,
-					q_vector->v_idx + vsi->base_vector);
-		} else {
+		i40e_update_enable_itr(vsi, q_vector);
+	} else { /* Legacy mode */
 		struct i40e_hw *hw = &vsi->back->hw;
 		/* We re-enable the queue 0 cause, but
 		 * don't worry about dynamic_enable
 		 * because we left it on for the other
 		 * possible interrupts during napi
 		 */
-			u32 qval = rd32(hw, I40E_QINT_RQCTL(0));
-			qval |= I40E_QINT_RQCTL_CAUSE_ENA_MASK;
-			wr32(hw, I40E_QINT_RQCTL(0), qval);
+		u32 qval = rd32(hw, I40E_QINT_RQCTL(0)) |
+			   I40E_QINT_RQCTL_CAUSE_ENA_MASK;
 
-			qval = rd32(hw, I40E_QINT_TQCTL(0));
-			qval |= I40E_QINT_TQCTL_CAUSE_ENA_MASK;
+		wr32(hw, I40E_QINT_RQCTL(0), qval);
+		qval = rd32(hw, I40E_QINT_TQCTL(0)) |
+		       I40E_QINT_TQCTL_CAUSE_ENA_MASK;
 		wr32(hw, I40E_QINT_TQCTL(0), qval);
-
 		i40e_irq_dynamic_enable_icr0(vsi->back);
 	}
-	}
-
 	return 0;
 }
 

drivers/net/ethernet/intel/i40evf/i40e_txrx.c

@@ -404,7 +404,7 @@ static void i40e_set_new_dynamic_itr(struct i40e_ring_container *rc)
 	 *  20-1249MB/s bulk   (8000 ints/s)
 	 */
 	bytes_per_int = rc->total_bytes / rc->itr;
-	switch (rc->itr) {
+	switch (new_latency_range) {
 	case I40E_LOWEST_LATENCY:
 		if (bytes_per_int > 10)
 			new_latency_range = I40E_LOW_LATENCY;
@@ -417,9 +417,14 @@ static void i40e_set_new_dynamic_itr(struct i40e_ring_container *rc)
 		break;
 	case I40E_BULK_LATENCY:
 		if (bytes_per_int <= 20)
-			rc->latency_range = I40E_LOW_LATENCY;
+			new_latency_range = I40E_LOW_LATENCY;
+		break;
+	default:
+		if (bytes_per_int <= 20)
+			new_latency_range = I40E_LOW_LATENCY;
 		break;
 	}
+	rc->latency_range = new_latency_range;
 
 	switch (new_latency_range) {
 	case I40E_LOWEST_LATENCY:
@@ -435,42 +440,14 @@ static void i40e_set_new_dynamic_itr(struct i40e_ring_container *rc)
 		break;
 	}
 
-	if (new_itr != rc->itr) {
-		/* do an exponential smoothing */
-		new_itr = (10 * new_itr * rc->itr) /
-			  ((9 * new_itr) + rc->itr);
-		rc->itr = new_itr & I40E_MAX_ITR;
-	}
+	if (new_itr != rc->itr)
+		rc->itr = new_itr;
 
 	rc->total_bytes = 0;
 	rc->total_packets = 0;
 }
 
-/**
- * i40e_update_dynamic_itr - Adjust ITR based on bytes per int
- * @q_vector: the vector to adjust
- **/
-static void i40e_update_dynamic_itr(struct i40e_q_vector *q_vector)
-{
-	u16 vector = q_vector->vsi->base_vector + q_vector->v_idx;
-	struct i40e_hw *hw = &q_vector->vsi->back->hw;
-	u32 reg_addr;
-	u16 old_itr;
-
-	reg_addr = I40E_VFINT_ITRN1(I40E_RX_ITR, vector - 1);
-	old_itr = q_vector->rx.itr;
-	i40e_set_new_dynamic_itr(&q_vector->rx);
-	if (old_itr != q_vector->rx.itr)
-		wr32(hw, reg_addr, q_vector->rx.itr);
-
-	reg_addr = I40E_VFINT_ITRN1(I40E_TX_ITR, vector - 1);
-	old_itr = q_vector->tx.itr;
-	i40e_set_new_dynamic_itr(&q_vector->tx);
-	if (old_itr != q_vector->tx.itr)
-		wr32(hw, reg_addr, q_vector->tx.itr);
-}
-
-/**
+/*
  * i40evf_setup_tx_descriptors - Allocate the Tx descriptors
  * @tx_ring: the tx ring to set up
  *
@@ -1280,6 +1257,68 @@ static int i40e_clean_rx_irq_1buf(struct i40e_ring *rx_ring, int budget)
 	return total_rx_packets;
 }
 
+/**
+ * i40e_update_enable_itr - Update itr and re-enable MSIX interrupt
+ * @vsi: the VSI we care about
+ * @q_vector: q_vector for which itr is being updated and interrupt enabled
+ *
+ **/
+static inline void i40e_update_enable_itr(struct i40e_vsi *vsi,
+					  struct i40e_q_vector *q_vector)
+{
+	struct i40e_hw *hw = &vsi->back->hw;
+	u16 old_itr;
+	int vector;
+	u32 val;
+
+	vector = (q_vector->v_idx + vsi->base_vector);
+	if (ITR_IS_DYNAMIC(vsi->rx_itr_setting)) {
+		old_itr = q_vector->rx.itr;
+		i40e_set_new_dynamic_itr(&q_vector->rx);
+		if (old_itr != q_vector->rx.itr) {
+			val = I40E_VFINT_DYN_CTLN_INTENA_MASK |
+			I40E_VFINT_DYN_CTLN_CLEARPBA_MASK |
+			(I40E_RX_ITR <<
+				I40E_VFINT_DYN_CTLN_ITR_INDX_SHIFT) |
+			(q_vector->rx.itr <<
+				I40E_VFINT_DYN_CTLN_INTERVAL_SHIFT);
+		} else {
+			val = I40E_VFINT_DYN_CTLN_INTENA_MASK |
+			I40E_VFINT_DYN_CTLN_CLEARPBA_MASK |
+			(I40E_ITR_NONE <<
+				I40E_VFINT_DYN_CTLN_ITR_INDX_SHIFT);
+		}
+		if (!test_bit(__I40E_DOWN, &vsi->state))
+			wr32(hw, I40E_VFINT_DYN_CTLN1(vector - 1), val);
+	} else {
+		i40evf_irq_enable_queues(vsi->back, 1
+			<< q_vector->v_idx);
+	}
+	if (ITR_IS_DYNAMIC(vsi->tx_itr_setting)) {
+		old_itr = q_vector->tx.itr;
+		i40e_set_new_dynamic_itr(&q_vector->tx);
+		if (old_itr != q_vector->tx.itr) {
+			val = I40E_VFINT_DYN_CTLN_INTENA_MASK |
+				I40E_VFINT_DYN_CTLN_CLEARPBA_MASK |
+				(I40E_TX_ITR <<
+				   I40E_VFINT_DYN_CTLN_ITR_INDX_SHIFT) |
+				(q_vector->tx.itr <<
+				   I40E_VFINT_DYN_CTLN_INTERVAL_SHIFT);
+
+		} else {
+			val = I40E_VFINT_DYN_CTLN_INTENA_MASK |
+				I40E_VFINT_DYN_CTLN_CLEARPBA_MASK |
+				(I40E_ITR_NONE <<
+				   I40E_VFINT_DYN_CTLN_ITR_INDX_SHIFT);
+		}
+		if (!test_bit(__I40E_DOWN, &vsi->state))
+			wr32(hw, I40E_VFINT_DYN_CTLN1(vector - 1), val);
+	} else {
+		i40evf_irq_enable_queues(vsi->back,
+					 1 << q_vector->v_idx);
+	}
+}
+
 /**
  * i40evf_napi_poll - NAPI polling Rx/Tx cleanup routine
  * @napi: napi struct with our devices info in it
@@ -1336,13 +1375,7 @@ int i40evf_napi_poll(struct napi_struct *napi, int budget)
 
 	/* Work is done so exit the polling mode and re-enable the interrupt */
 	napi_complete(napi);
-	if (ITR_IS_DYNAMIC(vsi->rx_itr_setting) ||
-	    ITR_IS_DYNAMIC(vsi->tx_itr_setting))
-		i40e_update_dynamic_itr(q_vector);
-
-	if (!test_bit(__I40E_DOWN, &vsi->state))
-		i40evf_irq_enable_queues(vsi->back, 1 << q_vector->v_idx);
-
+	i40e_update_enable_itr(vsi, q_vector);
 	return 0;
 }