net/mlx5: fix legacy non-inline multi-packet performance
Checks
Commit Message
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@mellanox.com>
---
drivers/net/mlx5/mlx5_prm.h | 2 ++
drivers/net/mlx5/mlx5_rxtx.c | 4 +++-
2 files changed, 5 insertions(+), 1 deletion(-)
Comments
From: Viacheslav Ovsiienko
> 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@mellanox.com>
Acked-by: Matan Azrad <matan@mellanox.com>
27/11/2019 14:53, Matan Azrad:
> From: Viacheslav Ovsiienko
> > 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@mellanox.com>
> Acked-by: Matan Azrad <matan@mellanox.com>
Applied, thanks
@@ -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
@@ -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))