On Apr 11, 2016, at 2:38 PM, dpchoudh . wrote:
>
> If the vendor of a new type of fabric wants to include support for OpenMPI,
> then, as long as they can implement a libfabric provider, they can use the
> OFI MTL without adding any code to the OpenMPI source tree itself.
If you implement the
Hi Howard and all
Thank you very much for the information. I have a follow up question:
If the vendor of a new type of fabric wants to include support for OpenMPI,
then, as long as they can implement a libfabric provider, they can use the
OFI MTL without adding any code to the OpenMPI source tree
George Bosilca writes:
> MPI_Wtick is not about the precision but about the resolution of the
> underlying timer (aka. the best you can hope to get).
What's the distinction here? (clock_getres(2) says "resolution
(precision)".)
My point (like JH's?) is that it doesn't generally return the inte
Jeff Hammond writes:
> George:
>
> Indeed, MPI_Wtick is not always a good measure of the precision of
> MPI_Wtime. The way I would measure resolution is to call MPI_Wtime a few
> million times.
Is there typically a problem with just looping until the result changes
a few times? Obviously if th
For two-sided Open MPI uses CMA, XPMEM, or KNEM for single-copy shared
memory if available. Otherwise it does two copies.
-Nathan
On Mon, Apr 11, 2016 at 09:02:38AM -0700, Jeff Hammond wrote:
>MPI-3 shared memory gives you direct access, meaning potentially zero
>copies if you eg just re
MPI-3 shared memory gives you direct access, meaning potentially zero
copies if you eg just read shared state.
Optimizing intranode MPI comm just reduces copies. Since MPI comm semantics
require one copy, you can't do better in RMA. In Send-Recv, I guess you can
do only one copy with a CMA impleme
Hello,
I have been looking into the MPI-3 extensions that added ways to do
direct memory copying on multi-core 'nodes' that share memory.
Architectures constructed from these nodes are universal now, so
improved ways to exploit them are certainly needed. However, it is my
understanding that
