A bus error occurs in sm OSC under the following conditions.
- sparc64 or any other architectures which need strict alignment.
- `MPI_WIN_POST` or `MPI_WIN_START` is called for a window created
by sm OSC.
- The communicator size is odd and greater than 3.
The lines 283-285 in current `ompi/mca/osc/sm/osc_sm_component.c` has
the following code.
```c
module->global_state = (ompi_osc_sm_global_state_t *) (module->segment_base);
module->node_states = (ompi_osc_sm_node_state_t *) (module->global_state + 1);
module->posts[0] = (uint64_t *) (module->node_states + comm_size);
```
The size of `ompi_osc_sm_node_state_t` is multiples of 4 but not
multiples of 8. So if `comm_size` is odd, `module->posts[0]` does
not aligned to 8. This causes a bus error when accessing
`module->posts[i][j]`.
This patch fixes the alignment of `module->posts[0]` by setting
`module->posts[0]` first.
The osc/sm component was using a simple counter to determine if all
expected posts had arrived to start a PSCW access epoch. This is
incorrect as a post may arrive from a peer that isn't part of the
current start group. There are many ways this could have been fixed.
This commit adds an n^2 bitmap. When a process posts it sets a bit in
the bitmap associated with the access rank to indicate the post is
complete. The access rank checks for and clears the bits associated
with all the processes in the start group.
The bitmap requires comm_size ^ 2 bits of space. This should be
managable as most nodes have relatively small numbers of processes. If
this changes another algorigthm can be implemented.
Signed-off-by: Nathan Hjelm <hjelmn@lanl.gov>
- MPI_Compare_and_swap
- MPI_Fetch_and_op
- MPI_Raccumulate
- MPI_Win_detach
Thanks to Michael Knobloch and Takahiro Kawashima for bringing this
to our attention
Use of the old ompi_free_list_t and ompi_free_list_item_t is
deprecated. These classes will be removed in a future commit.
This commit updates the entire code base to use opal_free_list_t and
opal_free_list_item_t.
Notes:
OMPI_FREE_LIST_*_MT -> opal_free_list_* (uses opal_using_threads ())
Signed-off-by: Nathan Hjelm <hjelmn@lanl.gov>
Initialize the blocking_fence flag to false as the code logic indicates that it should only be set if someone provides that flag.
Thanks to Lisandro Dalcin for reporting it
cmr=v1.8.4:reviewer=hjelmn
This commit was SVN r32812.
WHAT: Open our low-level communication infrastructure by moving all necessary components (btl/rcache/allocator/mpool) down in OPAL
All the components required for inter-process communications are currently deeply integrated in the OMPI layer. Several groups/institutions have express interest in having a more generic communication infrastructure, without all the OMPI layer dependencies. This communication layer should be made available at a different software level, available to all layers in the Open MPI software stack. As an example, our ORTE layer could replace the current OOB and instead use the BTL directly, gaining access to more reactive network interfaces than TCP. Similarly, external software libraries could take advantage of our highly optimized AM (active message) communication layer for their own purpose. UTK with support from Sandia, developped a version of Open MPI where the entire communication infrastucture has been moved down to OPAL (btl/rcache/allocator/mpool). Most of the moved components have been updated to match the new schema, with few exceptions (mainly BTLs where I have no way of compiling/testing them). Thus, the completion of this RFC is tied to being able to completing this move for all BTLs. For this we need help from the rest of the Open MPI community, especially those supporting some of the BTLs. A non-exhaustive list of BTLs that qualify here is: mx, portals4, scif, udapl, ugni, usnic.
This commit was SVN r32317.
Brad correctly pointed out that the total window size should not be an
int. Changed it to an unsigned long.
cmr=v1.8.2:reviewer=bbenton
This commit was SVN r32010.
Only one field is valid for RMA requests: MPI_ERROR. This field is set
to the correct value in ompi_request_empty so there is no reason to
allocate and keep track of osc/sm requests because they are always
complete on return. Since we are no longer using the osc/sm request
structure or free list they are now removed.
Closes trac:4723
Tracking this issue with the CMR. Brad, can you verify the issue is indeed fixed.
cmr=v1.8.2:reviewer=bbenton
This commit was SVN r32009.
The following Trac tickets were found above:
Ticket 4723 --> https://svn.open-mpi.org/trac/ompi/ticket/4723
Fixed two bugs:
- Use module->comm NOT comm to get the CID for the shared memory backing
file. This fixes the case where there are multiple shared memory windows
at the same time.
- Remember to unlink the shared memory backing file.
Refs trac:4438
cmr=v1.8:reviewer=jsquyres
This commit was SVN r31227.
The following Trac tickets were found above:
Ticket 4438 --> https://svn.open-mpi.org/trac/ompi/ticket/4438
- Fix several typos is osc/rdma.
- Fix a locking issue in osc/sm that was caused by an incorrect
assumption about the semantics of opal_atomic_add_32.
- Always unlock the accumulation lock in osc/sm.
- The base of a processes shared memory window should be NULL if
the size is zero. Fixed.
cmr=v1.7.5:ticket=trac:4304
This commit was SVN r30853.
The following Trac tickets were found above:
Ticket 4304 --> https://svn.open-mpi.org/trac/ompi/ticket/4304
