***SPAM*** Re: [ofa-general] local DMA transfer?

[Dotan Barak]

On Sat, Jan 17, 2009 at 9:38 PM, Yicheng Jia <YJia at tmriusa.com> wrote:
>
> Hi Dotan,
>
> Does HCA provide any internal route for local DMA so that local data
> transfer doesn't has to go out of the HCA port as regular QPs do? In another
> word, it's not efficient to use QPs for local DMA transfer, is it true?

Yes, the HCA provide internal route within the IB port (it called
internal loopback).
The HCA recognize that the packets should be routed
to its own QP, so the packets don't go out through the IB port.

I don't know if this is efficient as memcpy, but i think that you can
use it safely without any worry of performance or correctness issues.

Dotan