diff mbox series

[net-next,v2,2/3] i40e: eliminate division in napi_poll data path

Message ID 1592905458-850-3-git-send-email-magnus.karlsson@intel.com
State New
Headers show
Series i40e: improve AF_XDP performance | expand

Commit Message

Magnus Karlsson June 23, 2020, 9:44 a.m. UTC
Eliminate a division in the napi_poll data path. This division is
executed even though it is only needed in the rare case when there are
not enough interrupt lines so they have to be shared between queue
pairs. Instead, just test for this case and only execute the division
if needed. The code has been lifted from the ice driver.

Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
---
 drivers/net/ethernet/intel/i40e/i40e_txrx.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)
diff mbox series

Patch

diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.c b/drivers/net/ethernet/intel/i40e/i40e_txrx.c
index 9334abd..60fa102 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_txrx.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_txrx.c
@@ -2595,10 +2595,16 @@  int i40e_napi_poll(struct napi_struct *napi, int budget)
 	if (budget <= 0)
 		goto tx_only;
 
-	/* 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.
-	 */
-	budget_per_ring = max(budget/q_vector->num_ringpairs, 1);
+	/* normally we have 1 Rx ring per q_vector */
+	if (unlikely(q_vector->num_ringpairs > 1))
+		/* 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.
+		 */
+		budget_per_ring = max_t(int, budget / q_vector->num_ringpairs, 1);
+	else
+		/* Max of 1 Rx ring in this q_vector so give it the budget */
+		budget_per_ring = budget;
 
 	i40e_for_each_ring(ring, q_vector->rx) {
 		int cleaned = ring->xsk_umem ?