Replace the SMP barrier with atomic thread fence for iavf hw ring scan in the bulk Rx path.
This patch introduces a change to the iavf driver that was already added to the i40e driver [1] as part of the adoption of the use of compiler atomics. [1] https://patches.dpdk.org/project/dpdk/patch/20210706065404.25137-3- joyce.k...@arm.com/ Signed-off-by: Kathleen Capella <kathleen.cape...@arm.com> Reviewed-by: Joyce Kong <joyce.k...@arm.com> --- drivers/net/iavf/iavf_rxtx.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/net/iavf/iavf_rxtx.c b/drivers/net/iavf/iavf_rxtx.c index cb779879cb..47f12a9b28 100644 --- a/drivers/net/iavf/iavf_rxtx.c +++ b/drivers/net/iavf/iavf_rxtx.c @@ -1843,7 +1843,8 @@ iavf_rx_scan_hw_ring_flex_rxd(struct iavf_rx_queue *rxq) for (j = IAVF_LOOK_AHEAD - 1; j >= 0; j--) s[j] = rte_le_to_cpu_16(rxdp[j].wb.status_error0); - rte_smp_rmb(); + /* This barrier is to order loads of different words in the descriptor */ + rte_atomic_thread_fence(__ATOMIC_ACQUIRE); /* Compute how many contiguous DD bits were set */ for (j = 0, nb_dd = 0; j < IAVF_LOOK_AHEAD; j++) { @@ -1946,7 +1947,8 @@ iavf_rx_scan_hw_ring(struct iavf_rx_queue *rxq) IAVF_RXD_QW1_STATUS_SHIFT; } - rte_smp_rmb(); + /* This barrier is to order loads of different words in the descriptor */ + rte_atomic_thread_fence(__ATOMIC_ACQUIRE); /* Compute how many contiguous DD bits were set */ for (j = 0, nb_dd = 0; j < IAVF_LOOK_AHEAD; j++) { -- 2.17.1
