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authorEli Cohen <eli@mellanox.com>2016-06-10 00:07:40 +0300
committerDavid S. Miller <davem@davemloft.net>2016-06-09 22:06:27 -0700
commit0ca00fc1f808602137dc6d51f17747b3bb0fc34d (patch)
tree99110cd4a64dcf09a4357d33bd74fe6c53c083fc
parent811afeaa3797bdf4eabed286100811b33005c9e0 (diff)
downloadlinux-0ca00fc1f808602137dc6d51f17747b3bb0fc34d.tar.gz
net/mlx5e: Fix blue flame quota logic
Blue flame is a latency enhancement feature that allows the driver to write the packet data directly to the NIC's registers thus making the read of the packet data from host memory redundant. We maintain a quota for the blue flame which is reloaded whenever we identify that the hardware is processing send requests and processes them fast enough so by the time we post the next send request it was able to process all the pending ones. This indicates that the hardware is capable of processing more blue flame requests efficiently. The blue flame quota is decremented whenever we send using blue flame. The current code erroneously clears the budget if we did not use blue flame for the current post send operation and we fix it here. Fixes: 88a85f99e51f ('net/mlx5e: TX latency optimization to save DMA reads') Signed-off-by: Eli Cohen <eli@mellanox.com> Signed-off-by: Saeed Mahameed <saeedm@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--drivers/net/ethernet/mellanox/mlx5/core/en_tx.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_tx.c b/drivers/net/ethernet/mellanox/mlx5/core/en_tx.c
index 229ab16fb8d3..b000ddc29553 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_tx.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_tx.c
@@ -317,7 +317,8 @@ static netdev_tx_t mlx5e_sq_xmit(struct mlx5e_sq *sq, struct sk_buff *skb)
while ((sq->pc & wq->sz_m1) > sq->edge)
mlx5e_send_nop(sq, false);
- sq->bf_budget = bf ? sq->bf_budget - 1 : 0;
+ if (bf)
+ sq->bf_budget--;
sq->stats.packets++;
sq->stats.bytes += num_bytes;