ixgbe: Default to queue pairs when number of queues is less than CPUs

The old code had several errors in how it was determining the vector
budget.  In order to simplify things this patch updates the code so that it
will attempt to always allocated paired Rx/Tx vectors instead of attempting
to allocate individual vectors when the number of queues is less than the
number of CPUs.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Tested-by: Stephen Ko <stephen.s.ko@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe.h b/drivers/net/ethernet/intel/ixgbe/ixgbe.h
index c5cd2b678b443771209754efaa4fbac0cff87795..f25b4e2f8c57bd2747ae956dda049248a3d75284 100644 (file)
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe.h
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe.h
@@ -370,7 +370,7 @@ static inline u16 ixgbe_desc_unused(struct ixgbe_ring *ring)
 #define MAX_MSIX_Q_VECTORS MAX_MSIX_Q_VECTORS_82599
 #define MAX_MSIX_COUNT MAX_MSIX_VECTORS_82599
 
-#define MIN_MSIX_Q_VECTORS 2
+#define MIN_MSIX_Q_VECTORS 1
 #define MIN_MSIX_COUNT (MIN_MSIX_Q_VECTORS + NON_Q_VECTORS)
 
 /* default to trying for four seconds */

diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
index bad9c0508dfe752540e78c0717f6a761cf49c6cd..80ae91902aab2d061e1bcb36f56cd97118877422 100644 (file)
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
@@ -4561,11 +4561,9 @@ static void ixgbe_acquire_msix_vectors(struct ixgbe_adapter *adapter,
 {
        int err, vector_threshold;
 
-       /* We'll want at least 3 (vector_threshold):
-        * 1) TxQ[0] Cleanup
-        * 2) RxQ[0] Cleanup
-        * 3) Other (Link Status Change, etc.)
-        * 4) TCP Timer (optional)
+       /* We'll want at least 2 (vector_threshold):
+        * 1) TxQ[0] + RxQ[0] handler
+        * 2) Other (Link Status Change, etc.)
         */
        vector_threshold = MIN_MSIX_COUNT;
 
@@ -4919,9 +4917,11 @@ static int ixgbe_set_interrupt_capability(struct ixgbe_adapter *adapter)
         * doesn't do us much good if we have a lot more vectors
         * than CPU's.  So let's be conservative and only ask for
         * (roughly) the same number of vectors as there are CPU's.
+        * The default is to use pairs of vectors.
         */
-       v_budget = min(adapter->num_rx_queues + adapter->num_tx_queues,
-                      (int)num_online_cpus()) + NON_Q_VECTORS;
+       v_budget = max(adapter->num_rx_queues, adapter->num_tx_queues);
+       v_budget = min_t(int, v_budget, num_online_cpus());
+       v_budget += NON_Q_VECTORS;
 
        /*
         * At the same time, hardware can only support a maximum of