Re: [PATCH v2 1/3] net/bonding: support Tx prepare

[Chas Williams <3chas3@gmail.com>]

On 9/13/22 06:22, Ferruh Yigit wrote:
> On 7/25/2022 5:08 AM, Chengwen Feng wrote:
>
>
> I assume intention is to make this as transparent as possible to the
> user, that is why you are using a wrapper that combines
> `rte_eth_tx_prepare()` & `rte_eth_tx_burst()` APIs. But for other PMDs
> `rte_eth_tx_burst()` is called explicitly by the application.
>
> Path is also adding two new bonding specific APIs to enable/disable Tx
> prepare.
> Instead if you leave calling `rte_eth_tx_prepare()` decision to user,
> there will be no need for the enable/disable Tx prepare APIs and the
> wrapper.
>
> The `tx_pkt_prepare()` implementation in bonding can do the mode check,
> call Tx prepare for all slaves and apply failure recovery, as done in
> this wrapper function, what do you think, will it work?
>

If you leave calling tx_prepare to the user, you need to perform a
hash calculation to determine an output device. Since the output
devices might be different types, you really need to know which
device's tx_prepare needs to be called. You potentially will calculate
the packet hash twice. While you could be clever with storing the hash
in the mbuf somewhere, that's likely more complicated.