vmxnet3: set RX interrupt pending only when needed

When an RX thread handles more than one RX queue and has a mix of
queues in interrupt mode and polling mode, the RX input routine is
naturally in polling mode. In that case, there is no need to set RX
interrupt pending when descriptor is available in the queue for
interrupt mode.

Type: fix

Signed-off-by: Steven Luong <sluong@cisco.com>
Change-Id: Iedbe57941eca3152c0e8ab9096cc81f315e0a915

1 files changed, 38 insertions, 5 deletions

diff --git a/src/plugins/vmxnet3/vmxnet3.c b/src/plugins/vmxnet3/vmxnet3.c
index ff0a7dc706b..16d7d86fb3a 100644
--- a/src/plugins/vmxnet3/vmxnet3.c
+++ b/src/plugins/vmxnet3/vmxnet3.c
@@ -69,11 +69,23 @@ vmxnet3_interface_rx_mode_change (vnet_main_t * vnm, u32 hw_if_index, u32 qid,
   vnet_hw_interface_t *hw = vnet_get_hw_interface (vnm, hw_if_index);
   vmxnet3_device_t *vd = pool_elt_at_index (vmxm->devices, hw->dev_instance);
   vmxnet3_rxq_t *rxq = vec_elt_at_index (vd->rxqs, qid);
+  vmxnet3_per_thread_data_t *ptd;
 
-  if (mode == VNET_HW_IF_RX_MODE_POLLING)
-    rxq->int_mode = 0;
+  if (mode == rxq->mode)
+    return 0;
+  if ((mode != VNET_HW_IF_RX_MODE_POLLING) &&
+      (mode != VNET_HW_IF_RX_MODE_INTERRUPT))
+    return clib_error_return (0, "Rx mode %U not supported",
+			      format_vnet_hw_if_rx_mode, mode);
+  rxq->mode = mode;
+  ptd = vec_elt_at_index (vmxm->per_thread_data, rxq->thread_index);
+  if (rxq->mode == VNET_HW_IF_RX_MODE_POLLING)
+    ptd->polling_q_count++;
   else
-    rxq->int_mode = 1;
+    {
+      ASSERT (ptd->polling_q_count != 0);
+      ptd->polling_q_count--;
+    }
 
   return 0;
 }
@@ -288,6 +300,7 @@ vmxnet3_rxq_init (vlib_main_t * vm, vmxnet3_device_t * vd, u16 qid, u16 qsz)
   rxq = vec_elt_at_index (vd->rxqs, qid);
   clib_memset (rxq, 0, sizeof (*rxq));
   rxq->size = qsz;
+  rxq->mode = VNET_HW_IF_RX_MODE_POLLING;
   for (rid = 0; rid < VMXNET3_RX_RING_SIZE; rid++)
     {
       rxq->rx_desc[rid] = vlib_physmem_alloc_aligned_on_numa
@@ -534,8 +547,13 @@ vmxnet3_rxq_irq_handler (vlib_main_t * vm, vlib_pci_dev_handle_t h, u16 line)
   u16 qid = line;
   vmxnet3_rxq_t *rxq = vec_elt_at_index (vd->rxqs, qid);
 
-  if (vec_len (vd->rxqs) > qid && vd->rxqs[qid].int_mode != 0)
-    vnet_hw_if_rx_queue_set_int_pending (vnm, rxq->queue_index);
+  if (vec_len (vd->rxqs) > qid && (rxq->mode != VNET_HW_IF_RX_MODE_POLLING))
+    {
+      vmxnet3_per_thread_data_t *ptd =
+	vec_elt_at_index (vmxm->per_thread_data, rxq->thread_index);
+      if (ptd->polling_q_count == 0)
+	vnet_hw_if_rx_queue_set_int_pending (vnm, rxq->queue_index);
+    }
 }
 
 static void
@@ -815,12 +833,20 @@ vmxnet3_create_if (vlib_main_t * vm, vmxnet3_create_if_args_t * args)
   {
     vmxnet3_rxq_t *rxq = vec_elt_at_index (vd->rxqs, qid);
     u32 qi, fi;
+    vmxnet3_per_thread_data_t *ptd;
 
     qi = vnet_hw_if_register_rx_queue (vnm, vd->hw_if_index, qid,
 				       VNET_HW_IF_RXQ_THREAD_ANY);
     fi = vlib_pci_get_msix_file_index (vm, vd->pci_dev_handle, qid);
     vnet_hw_if_set_rx_queue_file_index (vnm, qi, fi);
     rxq->queue_index = qi;
+    rxq->thread_index =
+      vnet_hw_if_get_rx_queue_thread_index (vnm, rxq->queue_index);
+    if (rxq->mode == VNET_HW_IF_RX_MODE_POLLING)
+      {
+	ptd = vec_elt_at_index (vmxm->per_thread_data, rxq->thread_index);
+	ptd->polling_q_count++;
+      }
     rxq->buffer_pool_index =
       vnet_hw_if_get_rx_queue_numa_node (vnm, rxq->queue_index);
     vmxnet3_rxq_refill_ring0 (vm, vd, rxq);
@@ -886,7 +912,14 @@ vmxnet3_delete_if (vlib_main_t * vm, vmxnet3_device_t * vd)
       vmxnet3_rxq_t *rxq = vec_elt_at_index (vd->rxqs, i);
       u16 mask = rxq->size - 1;
       u16 rid;
+      vmxnet3_per_thread_data_t *ptd =
+	vec_elt_at_index (vmxm->per_thread_data, rxq->thread_index);
 
+      if (rxq->mode == VNET_HW_IF_RX_MODE_POLLING)
+	{
+	  ASSERT (ptd->polling_q_count != 0);
+	  ptd->polling_q_count--;
+	}
       for (rid = 0; rid < VMXNET3_RX_RING_SIZE; rid++)
 	{
 	  vmxnet3_rx_ring *ring;