[dpdk-dev] [PATCH] net/mlx5: poll completion queue once per a call

[Sagi Grimberg]

> mlx5_tx_complete() polls completion queue multiple times until it
> encounters an invalid entry. As Tx completions are suppressed by
> MLX5_TX_COMP_THRESH, it is waste of cycles to expect multiple completions
> in a poll. And freeing too many buffers in a call can cause high jitter.
> This patch improves throughput a little.

What if the device generates burst of completions? Holding these
completions un-reaped can theoretically cause resource stress on
the corresponding mempool(s).

I totally get the need for a stopping condition, but is "loop once"
the best stop condition?

Perhaps an adaptive budget (based on online stats) perform better?