Re: [PATCH] ip_frag: add IPv4 fast fragment switch and test data

[Konstantin Ananyev <konstantin.v.ananyev@yandex.ru>]

04/06/2022 03:19, Huichao Cai пишет:
> I've seen some applications that have to rewrite fragment
> functions themselves in order to use MBUF_FAST_FREE
> features, such as iQiYi's DPVS.
> 
> 


I am not sure that it will really help to improve performance,
as if you have a lot of packets to fragment, you'll probably
spend more time copying them.
Might be it will help somehow if you'll have
very rare occurrence of such packets.
Also please keep in mind, that ip_frag is not the only
one that does use indirect mbufs and refcnt.
As another example - GSO implementation.
So application writer has to be extremely careful
when enabling MBUF_FAST_FREE.
My personal advice - just don't use it,
though I am quite conservative here.

Anyway, as I said before, if there is a real use-case for it -
I am ok to introduce new function that would do copying
while fragmenting.

Konstantin