On Tue Jul 10, 2018 15:21:13, Harms, Kevin wrote:
Harms, Does the mosview feature use the existing Linux
Harms, namespace work  or is this something custom for mOS?
mosview is orthogonal to Linux namespaces. Independent of the mOS view
you are in, files, mounts, processes, etc. are visible as before.
Currently mosview is off by default and we are still discussing what the
exact behavior should be with runtime systems people.
Until now, if you looked in /proc or /sys you would see (mostly) all
of memory and CPUs. What mosview does, is to limit what is visible.
From either the Linux or the LWK side you can now choose whether you
want to see all, only Linux resources, or only LWK resources.
The reason we need this is that some programs and runtimes make
decisions based on the resources they can see. For example, the Intel
optimized HPL sees CPU 0 and tries to run on it, even if that CPU is
not reserved for it.
Similarly, in a workflow example that uses both kernels, those on the
Linux side should only see Linux resources as available so they can
optimize themselves around the Linux resources. The LWK processes in
this scenario should remain within that partition.
The problem we are running into is that many programs and libraries make
assumptions about what resources they can use and they conflict with our
strict partitioning model. Most of these implementations are broken and
not specific to mOS. Running just Linux, and off-lining memory and CPUs
would break them as well.
There is no solution that works for every situation. That's why mosview
is flexible and off by default at the moment. We are continuing our
discussions with various parties to refine this approach.
Rolf Riesen, Ph.D. Email: rolf.riesen(a)intel.com
Software Architect Phone: +1 (503) 613-5514
Extreme-scale Software System Pathfinding Mobile: +1 (505) 363-6871
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