Yes, I was going to aggregate some of the conversations that I have had
(four of them, thank you much for the responses). The consensus was
that neither hwloc nor OpenMPI were appropriate for my project.
The use of shared memory was proposed by Jeff Squyres and one other
person. From there is it a matter of deciding between interrupt driven
messaging or semaphores. This (apparently unpublished) paper discusses
the pros and cons of each:
http://cs.brown.edu/people/irina/papers/2013-opodis.pdf
One of the first approaches they discuss is Barrelfish OS, which looks
to be comparable to an exokernel running an image of the OS on each CPU
node:
http://www.barrelfish.org/
This appears to have a robust shared memory approach. I'm still
digesting the details, but it looks to solve many of the problems I am
looking at.
Thanks again for the discussions!
tim
Jeff Squyres (jsquyres) wrote:
To follow up for the web thread: I talked with Tim about this off-list.
Not only will Open MPI likely not work in Tim's environment, MPI itself is
probably too much for what he's trying to do.
On Mar 21, 2018, at 10:49 PM, Ralph H Castain <r...@open-mpi.org> wrote:
I don’t see how Open MPI can operate without pthreads
On Mar 19, 2018, at 3:23 PM, Gregory (tim) Kelly <gk...@sfu.ca> wrote:
Hello Everyone,
I'm inquiring to find someone that can answer some multi-part questions about
hwloc, OpenMPI and an alternative OS and toolchain. I have a project as part
of my PhD work, and it's not a simple, one-part question. For brevity, I am
omitting details about the OS and toolchain, other than that neither are
supported. If forced to choose between OpenMPI and the OS/toolchain, I am
likely to choose the OS/toolchain and pursue other avenues for parallelization.
That's part of what I am trying to determine with my inquiry.
To summarize some of the question areas:
1) The OS I am working with does not support MP
2) nor does it support pthreads
3) the hardware is quad-core SoC with an integrated memory controller
4) I'd like to see if it possible to utilize hwloc and shmem to build an
asymmetric multi-processing system where only one core has I/O but the other
three can run the executable
This is a fairly dedicated system to be used for analyzing ODEs (disease
models). The hardware is cheap ($200) and uses very little power (can run off
a 12v battery), and the toolchain and OS are all BSD-licensed (and everything
will be published under that license).
If someone is available for off-line discussion (to minimize unnecessary
traffic to the list), I'd be more than willing to summarize the conversation
and contribute it to the online documentation.
Thank you,
tim
--
"Nuclear power is a hell of a way to boil water." -- Albert Einstein
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