[mvapich-discuss] Questions in OSU OpenSHMEM Microbenchmarks

[Naveen Ravichandrasekaran]

Hi Jahanzeb,
Thanks for reply.
You are correct about the spec. The spec speaks about the size of pWrk in
terms of the number of elements.
In the benchmark, MAX(nreduce/2+1, _SHMEM_REDUCE_MIN_WRKDATA_SIZE) gives
you the correct number of elements.

But, the issue here is the symmetric heap allocation. As per the spec, when
we allocate the heap using shmem_malloc/shmalloc routines - we need to pass
the size of the array in bytes and not just the number of elements.
So, it still looks as an issue to me at that shmem_malloc/shmalloc
operation. Can you please verify?





On Tue, Dec 19, 2017 at 2:36 PM, Hashmi, Jahanzeb <
hashmi.29 at buckeyemail.osu.edu> wrote:

> Hi Naveen,
>
>
> The OpenSHMEM (1.3) specification document (page 58) states that:
> "The pWrk argument must have the same data type as dest. In C/C++, this
> contains
> max(nreduce/2 + 1, SHMEM_REDUCE_MIN_WRKDATA_SIZE) elements."
>
> http://www.openshmem.org/site/sites/default/site_files/OpenSHMEM-1.3.pdf
>
> The osu_oshm_reduce benchmark in OMB is following the OpenSHMEM standard.
> Further, the collective benchmarks in OpenSHMEM report number of elements
> instead of bytes as max_msg_size is 4M that corresponds to 1M float
> elements.
>
> Please let us know if there is any other issue.
>
> Thanks
>
> Jahanzeb
>
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