[ofa-general] SDP - How to?

[Zafar Gilani]

Hi,

Thank you for reply! My numbers are different may be because I am executing
MPJ Express (pure Java MPJ) over SDP. However now I need to implement code
in C now (natively). Any documentation that I may be able to use for
programming MPI using C Sockets and SDP?

Thanks

On Thu, Jun 11, 2009 at 11:22 AM, Amir Vadai <amirv at mellanox.co.il> wrote:

> Hi Zafar,
>
> I am the maintainer of SDP in OFED.
>
> The current SDP implementation does not have ZCopy. What we have is BCopy
> and something that we call BZcopy.
> Small packets (<=32k) are sent using BCopy - meaning the SEND verb is in
> use and data is not zero copied.
> Packets bigger than 32K are sent using BZcopy - they are also sent using
> the SEND verb but they are zero copied on the sender side. on the RX side
> packets are memcpy'ed.
> When we implement ZCopy it will be automatic too - when sending packets
> bigger than a threshold the driver will automatically use RDMA verb instead
> of the SEND.
>
> BTW, your numbers are different that what we measured. See attached. Was
> measured on a high end host using QDR IB PCI gen 2 and Mellanox ofed 1.4.
>
> - Amir
>

Zafar
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