4
–
Running MPI on QLogic Adapters
Open MPI
4-8
IB0054606-02 A
The default hardware context/CPU mappings can be changed on the QDR IB
Adapters (QLE734
x
“IB Hardware Contexts on the QDR IB Adapters” on
for more details.
Context sharing is enabled by default. How the system behaves when context
sharing is enabled or disabled is described in
“Enabling and Disabling Software
When running a job in a batch system environment where multiple jobs may be
running simultaneously, it is useful to restrict the number of IB contexts that are
made available on each node of an MPI. See
“Restricting IB Hardware Contexts in
a Batch Environment” on page 4-10
Errors that may occur with context sharing are covered in
There are multiple ways of specifying how processes are allocated. You can use
the
mpihosts
file, the
-np
and
-ppn
options with
mpirun
, and the
MPI_NPROCS
and
PSM_SHAREDCONTEXTS_MAX
environment variables. How
these all are set are covered later in this document.
IB Hardware Contexts on the QDR IB Adapters
On the QLE7340 and QLE7342 QDR adapters, adapter receive resources are
statically partitioned across the IB contexts according to the number of IB contexts
enabled. The following defaults are automatically set according to the number of
online CPUs in the node:
For four or less CPUs: 6 (4 + 2)
For five to eight CPUs: 10 (8 + 2)
For nine or more CPUs: 18 (16 + 2)
The one additional context on QDR adapters are to support the kernel on each
port.
Table 4-5. Available Hardware and Software Contexts
Adapter
Available Hardware
Contexts (same as number
of supported CPUs)
Available Contexts when
Software Context Sharing is
Enabled
QLE7342/
QLE7340
16
64
Summary of Contents for OFED+ Host
Page 1: ...IB0054606 02 A OFED Host Software Release 1 5 4 User Guide...
Page 14: ...xiv IB0054606 02 A OFED Host Software Release 1 5 4 User Guide...
Page 22: ...1 Introduction Interoperability 1 4 IB0054606 02 A...
Page 96: ...4 Running MPI on QLogic Adapters Debugging MPI Programs 4 24 IB0054606 02 A...
Page 140: ...6 SHMEM Description and Configuration SHMEM Benchmark Programs 6 32 IB0054606 02 A...
Page 148: ...8 Dispersive Routing 8 4 IB0054606 02 A...
Page 164: ...9 gPXE HTTP Boot Setup 9 16 IB0054606 02 A...
Page 176: ...A Benchmark Programs Benchmark 3 Messaging Rate Microbenchmarks A 12 IB0054606 02 A...
Page 202: ...B SRP Configuration OFED SRP Configuration B 26 IB0054606 02 A Notes...
Page 206: ...C Integration with a Batch Queuing System Clean up PSM Shared Memory Files C 4 IB0054606 02 A...
Page 238: ...E ULP Troubleshooting Troubleshooting SRP Issues E 20 IB0054606 02 A...
Page 242: ...F Write Combining Verify Write Combining is Working F 4 IB0054606 02 A Notes...
Page 280: ...G Commands and Files Summary of Configuration Files G 38 IB0054606 02 A...
Page 283: ......