[Mpi3-rma] [EXTERNAL] Re: Memory barriers in MPI_WIN_LOCK_ALL mode

Pavan Balaji balaji at mcs.anl.gov
Tue Oct 30 10:56:42 CDT 2012

On 10/30/2012 10:17 AM, Torsten Hoefler wrote:
>> for network operations, this is harder unless the network guarantees
>> that the data is placed in the remote memory.  This, for example, is
>> guaranteed by Mellanox adapters, but not by InfiniBand itself.
> Yes, I always assumed IB guarantees that but I couldn't cite the page
> of the standard. Isn't it that for an RDMA, the CQ entry will only
> appear at the source if the message is committed to remote memory?

No, it just means that it has been reliably delivered to the remote 
network adapter.  The Mellanox adapters, however, send the network 
hardware ACK only after they get the PCIe ACK for the memory commit.

  -- Pavan

Pavan Balaji

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