[dpdk-dev] [PATCH] net/mlx5: fix legacy non-inline multi-packet performance
Viacheslav Ovsiienko
viacheslavo at mellanox.com
Wed Nov 27 13:33:12 CET 2019
The legacy multi-packet write is the feature allowing to
put multiple packets into one transmitting descriptor,
this feature is supported by only NIC ConnectX-4LX.
The number of packets should be limited to provide
optimal size descriptor and better performance.
Fixes: 18a1c20044c0 ("net/mlx5: implement Tx burst template")
Signed-off-by: Viacheslav Ovsiienko <viacheslavo at mellanox.com>
---
drivers/net/mlx5/mlx5_prm.h | 2 ++
drivers/net/mlx5/mlx5_rxtx.c | 4 +++-
2 files changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/net/mlx5/mlx5_prm.h b/drivers/net/mlx5/mlx5_prm.h
index 651006b..2bac6a7 100644
--- a/drivers/net/mlx5/mlx5_prm.h
+++ b/drivers/net/mlx5/mlx5_prm.h
@@ -99,6 +99,8 @@
* in tx burst routine at the moment of freeing multiple mbufs.
*/
#define MLX5_EMPW_MAX_PACKETS MLX5_TX_COMP_THRESH
+#define MLX5_MPW_MAX_PACKETS 6
+
/*
* Default packet length threshold to be inlined with
* ordinary SEND. Inlining saves the MR key search
diff --git a/drivers/net/mlx5/mlx5_rxtx.c b/drivers/net/mlx5/mlx5_rxtx.c
index 73c16de..25d915c 100644
--- a/drivers/net/mlx5/mlx5_rxtx.c
+++ b/drivers/net/mlx5/mlx5_rxtx.c
@@ -3888,7 +3888,9 @@ enum mlx5_txcmp_code {
next_empw:
assert(NB_SEGS(loc->mbuf) == 1);
- part = RTE_MIN(pkts_n, MLX5_EMPW_MAX_PACKETS);
+ part = RTE_MIN(pkts_n, MLX5_TXOFF_CONFIG(MPW) ?
+ MLX5_MPW_MAX_PACKETS :
+ MLX5_EMPW_MAX_PACKETS);
if (unlikely(loc->elts_free < part)) {
/* We have no enough elts to save all mbufs. */
if (unlikely(loc->elts_free < MLX5_EMPW_MIN_PACKETS))
--
1.8.3.1
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