[PATCH V2 net 09/11] net: ena: optimise calculations for CQ doorbell
From: <hidden>
Date: 2019-06-03 14:44:30
Subsystem:
amazon ethernet drivers, networking drivers, the rest · Maintainers:
Arthur Kiyanovski, David Arinzon, Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
From: Sameeh Jubran <redacted> This patch initially checks if CQ doorbell is needed before proceeding with the calculations. Signed-off-by: Igor Chauskin <redacted> Signed-off-by: Sameeh Jubran <redacted> --- drivers/net/ethernet/amazon/ena/ena_eth_com.h | 20 ++++++++++--------- 1 file changed, 11 insertions(+), 9 deletions(-)
diff --git a/drivers/net/ethernet/amazon/ena/ena_eth_com.h b/drivers/net/ethernet/amazon/ena/ena_eth_com.h
index 0a3d9180e..77986c0ea 100644
--- a/drivers/net/ethernet/amazon/ena/ena_eth_com.h
+++ b/drivers/net/ethernet/amazon/ena/ena_eth_com.h@@ -195,15 +195,17 @@ static inline int ena_com_update_dev_comp_head(struct ena_com_io_cq *io_cq) u16 unreported_comp, head; bool need_update; - head = io_cq->head; - unreported_comp = head - io_cq->last_head_update; - need_update = unreported_comp > (io_cq->q_depth / ENA_COMP_HEAD_THRESH); - - if (io_cq->cq_head_db_reg && need_update) { - pr_debug("Write completion queue doorbell for queue %d: head: %d\n", - io_cq->qid, head); - writel(head, io_cq->cq_head_db_reg); - io_cq->last_head_update = head; + if (unlikely(io_cq->cq_head_db_reg)) { + head = io_cq->head; + unreported_comp = head - io_cq->last_head_update; + need_update = unreported_comp > (io_cq->q_depth / ENA_COMP_HEAD_THRESH); + + if (unlikely(need_update)) { + pr_debug("Write completion queue doorbell for queue %d: head: %d\n", + io_cq->qid, head); + writel(head, io_cq->cq_head_db_reg); + io_cq->last_head_update = head; + } } return 0;
--
2.17.1