From 4b5539c01ddf838ea6f5b67d00ee035231c8248a Mon Sep 17 00:00:00 2001 From: Magnus Karlsson Date: Tue, 23 Jun 2020 11:44:17 +0200 Subject: [PATCH] i40e: eliminate division in napi_poll data path 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 Tested-by: Andrew Bowers Signed-off-by: Tony Nguyen --- drivers/net/ethernet/intel/i40e/i40e_txrx.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.c b/drivers/net/ethernet/intel/i40e/i40e_txrx.c index aad4326ab0c9..3e5c566ceb01 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 ?