Discussion:
[OMPI users] pt2pt osc required for single-node runs?
Joseph Schuchart
2018-09-06 14:31:55 UTC
Permalink
All,

I installed Open MPI 3.1.2 on my laptop today (up from 3.0.0, which
worked fine) and ran into the following error when trying to create a
window:

```
--------------------------------------------------------------------------
The OSC pt2pt component does not support MPI_THREAD_MULTIPLE in this
release.
Workarounds are to run on a single node, or to use a system with an RDMA
capable network such as Infiniband.
--------------------------------------------------------------------------
[beryl:13894] *** An error occurred in MPI_Win_create
[beryl:13894] *** reported by process [2678849537,0]
[beryl:13894] *** on communicator MPI COMMUNICATOR 3 DUP FROM 0
[beryl:13894] *** MPI_ERR_WIN: invalid window
[beryl:13894] *** MPI_ERRORS_ARE_FATAL (processes in this communicator
will now abort,
[beryl:13894] *** and potentially your MPI job)
```

I remember seeing this announced in the release notes. I wonder,
however, why the pt2pt component is required for a run on a single node
(as suggested by the error message). I tried to disable the pt2pt
component, which gives a similar error but without the message about the
pt2pt component:

```
$ mpirun -n 4 --mca osc ^pt2pt ./a.out
[beryl:13738] *** An error occurred in MPI_Win_create
[beryl:13738] *** reported by process [2621964289,0]
[beryl:13738] *** on communicator MPI COMMUNICATOR 3 DUP FROM 0
[beryl:13738] *** MPI_ERR_WIN: invalid window
[beryl:13738] *** MPI_ERRORS_ARE_FATAL (processes in this communicator
will now abort,
[beryl:13738] *** and potentially your MPI job)
```

Is this a known issue with v3.1.2? Is there a way to get more
information about what is going wrong in the second case. Is this the
right way to disable the pt2pt component?

Cheers,
Joseph
Nathan Hjelm via users
2018-09-06 15:52:24 UTC
Permalink
You can either move to MPI_Win_allocate or try the v4.0.x snapshots. I will look at bringing the btl/vader support for osc/rdma back to v3.1.x. osc/pt2pt will probably never become truly thread safe.

-Nathan

On Sep 06, 2018, at 08:34 AM, Joseph Schuchart <***@hlrs.de> wrote:

All,

I installed Open MPI 3.1.2 on my laptop today (up from 3.0.0, which
worked fine) and ran into the following error when trying to create a
window:

```
--------------------------------------------------------------------------
The OSC pt2pt component does not support MPI_THREAD_MULTIPLE in this
release.
Workarounds are to run on a single node, or to use a system with an RDMA
capable network such as Infiniband.
--------------------------------------------------------------------------
[beryl:13894] *** An error occurred in MPI_Win_create
[beryl:13894] *** reported by process [2678849537,0]
[beryl:13894] *** on communicator MPI COMMUNICATOR 3 DUP FROM 0
[beryl:13894] *** MPI_ERR_WIN: invalid window
[beryl:13894] *** MPI_ERRORS_ARE_FATAL (processes in this communicator
will now abort,
[beryl:13894] *** and potentially your MPI job)
```

I remember seeing this announced in the release notes. I wonder,
however, why the pt2pt component is required for a run on a single node
(as suggested by the error message). I tried to disable the pt2pt
component, which gives a similar error but without the message about the
pt2pt component:

```
$ mpirun -n 4 --mca osc ^pt2pt ./a.out
[beryl:13738] *** An error occurred in MPI_Win_create
[beryl:13738] *** reported by process [2621964289,0]
[beryl:13738] *** on communicator MPI COMMUNICATOR 3 DUP FROM 0
[beryl:13738] *** MPI_ERR_WIN: invalid window
[beryl:13738] *** MPI_ERRORS_ARE_FATAL (processes in this communicator
will now abort,
[beryl:13738] *** and potentially your MPI job)
```

Is this a known issue with v3.1.2? Is there a way to get more
information about what is going wrong in the second case. Is this the
right way to disable the pt2pt component?

Cheers,
Joseph

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