Re: [lwip-users] LWIP/WIN32 UDP performance (throughtput)

[Simon Goldschmidt]

Sorry for not answering that post, I meant to, but somehow it slipped through...

Mason <address@hidden> wrote:
> > I don't think it's possible to use mem_malloc as a packet
> > buffer allocator, as there are other types of uses, e.g.
> > 
> >   dhcp = (struct dhcp *)mem_malloc(sizeof(struct dhcp));
> >   autoip = (struct autoip *)mem_malloc(sizeof(struct autoip));

These are not used if you init autoip and dhcp correctly (dhcp_set_struct(), 
autoip_set_struct()). I know that's not a good solution and we should add pools 
for it.

> > What I'd like is to be able to "redirect" pbuf_alloc to use
> > my buffer allocator, but the pbuf struct and the payload buffer
> > would not be contiguous, which violates the implicit assumptions
> > of PBUF_RAM pbufs, IIUC.
> > 
> > Have things changed on that front?

No, not yet. What's missing there are two things:
a) redirecting pbuf_alloc() to a custom function and
b) having a PBUF_REF-like type where pbuf_header works in both directions.

It shouldn't be too hard to implement, but I haven't even found the time to 
work much on the 1.4.1 release-related things, lately, so it might take some 
time until we get there :-(

> > If no, that means I have to memcpy every outgoing frame, right?

Not if would redirect mem_malloc(). However, your platform would need to allow 
the pbuf struct and payload be in contiguous memory, then.

> I did find this information on the lwip wiki
> http://lwip.wikia.com/wiki/Writing_a_device_driver#Notes_on_Zero-Copy_Network_interface_drivers
> 
> But I think it's a little bit dated?

Yeah, that doesn't really sum it up right. I don't think I have ever seen that 
article before...

Simon
-- 
Empfehlen Sie GMX DSL Ihren Freunden und Bekannten und wir
belohnen Sie mit bis zu 50,- Euro! https://freundschaftswerbung.gmx.de