Re: 回复: [RFC PATCH v1 0/4] Direct re-arming of buffers on receive side

[Thomas Monjalon <thomas@monjalon.net>]

[quick summary: ethdev API to bypass mempool]

18/01/2022 16:51, Ferruh Yigit:
> On 12/28/2021 6:55 AM, Feifei Wang wrote:
> > Morten Brørup <mb@smartsharesystems.com>:
> >> The patch provides a significant performance improvement, but I am
> >> wondering if any real world applications exist that would use this. Only a
> >> "router on a stick" (i.e. a single-port router) comes to my mind, and that is
> >> probably sufficient to call it useful in the real world. Do you have any other
> >> examples to support the usefulness of this patch?
> >>
> > One case I have is about network security. For network firewall, all packets need
> > to ingress on the specified port and egress on the specified port to do packet filtering.
> > In this case, we can know flow direction in advance.
> 
> I also have some concerns on how useful this API will be in real life,
> and does the use case worth the complexity it brings.
> And it looks too much low level detail for the application.

That's difficult to judge.
The use case is limited and the API has some severe limitations.
The benefit is measured with l3fwd, which is not exactly a real app.
Do we want an API which improves performance in limited scenarios
at the cost of breaking some general design assumptions?

Can we achieve the same level of performance with a mempool trick?