net/mlx5: fix minimum size of Multi-Packet Rx queue

Message ID 20180808193247.16391-1-yskoh@mellanox.com
State Accepted, archived
Headers show
Series
  • net/mlx5: fix minimum size of Multi-Packet Rx queue
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Checks

Context Check Description
ci/Intel-compilation success Compilation OK
ci/checkpatch success coding style OK

Commit Message

Yongseok Koh Aug. 8, 2018, 7:32 p.m.
The size of Rx queue is determined by dividing the number of descriptors by
the number of strides. As device can't support single slot queue, if the
number of descriptors is same as the number of strides, MPRQ shouldn't be
enabled. Otherwise, this will cause HW fault. For example, if rxd is set to
512 with testpmd on ConnectX-4 Lx, PMD can't receive more than 512 packets
because the minimum number of strides for ConnectX-4 Lx is 512. Users have
to configure larger number of descriptors in this case.

Fixes: 7d6bf6b866b8 ("net/mlx5: add Multi-Packet Rx support")
Cc: stable@dpdk.org

Signed-off-by: Yongseok Koh <yskoh@mellanox.com>
---
 drivers/net/mlx5/mlx5_rxq.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

Comments

Thomas Monjalon Aug. 9, 2018, 10:20 a.m. | #1
08/08/2018 21:32, Yongseok Koh:
> The size of Rx queue is determined by dividing the number of descriptors by
> the number of strides. As device can't support single slot queue, if the
> number of descriptors is same as the number of strides, MPRQ shouldn't be
> enabled. Otherwise, this will cause HW fault. For example, if rxd is set to
> 512 with testpmd on ConnectX-4 Lx, PMD can't receive more than 512 packets
> because the minimum number of strides for ConnectX-4 Lx is 512. Users have
> to configure larger number of descriptors in this case.
> 
> Fixes: 7d6bf6b866b8 ("net/mlx5: add Multi-Packet Rx support")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Yongseok Koh <yskoh@mellanox.com>

Applied, thanks

Patch

diff --git a/drivers/net/mlx5/mlx5_rxq.c b/drivers/net/mlx5/mlx5_rxq.c
index 8b4c1b1a14..1f7bfd4414 100644
--- a/drivers/net/mlx5/mlx5_rxq.c
+++ b/drivers/net/mlx5/mlx5_rxq.c
@@ -1356,7 +1356,7 @@  mlx5_rxq_new(struct rte_eth_dev *dev, uint16_t idx, uint16_t desc,
 		sizeof(struct rte_mbuf_ext_shared_info) +
 		RTE_PKTMBUF_HEADROOM;
 	if (mprq_en &&
-	    desc >= (1U << config->mprq.stride_num_n) &&
+	    desc > (1U << config->mprq.stride_num_n) &&
 	    mprq_stride_size <= (1U << config->mprq.max_stride_size_n)) {
 		/* TODO: Rx scatter isn't supported yet. */
 		tmpl->rxq.sges_n = 0;
@@ -1411,6 +1411,14 @@  mlx5_rxq_new(struct rte_eth_dev *dev, uint16_t idx, uint16_t desc,
 			dev->data->dev_conf.rxmode.max_rx_pkt_len,
 			mb_len - RTE_PKTMBUF_HEADROOM);
 	}
+	if (mprq_en && !mlx5_rxq_mprq_enabled(&tmpl->rxq))
+		DRV_LOG(WARNING,
+			"port %u MPRQ is requested but cannot be enabled"
+			" (requested: desc = %u, stride_sz = %u,"
+			" supported: min_stride_num = %u, max_stride_sz = %u).",
+			dev->data->port_id, desc, mprq_stride_size,
+			(1 << config->mprq.stride_num_n),
+			(1 << config->mprq.max_stride_size_n));
 	DRV_LOG(DEBUG, "port %u maximum number of segments per packet: %u",
 		dev->data->port_id, 1 << tmpl->rxq.sges_n);
 	if (desc % (1 << tmpl->rxq.sges_n)) {