6
–
SHMEM Description and Configuration
Environment Variables
IB0054606-02 A
6-13
SHMEM's long message protocol is disabled. This is because the long
message protocol implementation does not support passive progress. The
effect of disabling this is to reduce long message bandwidth to that which
can be achieved with the short message protocol. There is no effect on the
bandwidth for message sizes below the long message break-point, which is
set to 16KB by default.
Active versus Passive Progress
It is expected that most applications will be run with QLogic SHMEM's active
progress mode since this gives full performance. The passive progress mode will
typically be used in the following circumstances:
For applications that use a polling idiom that is incompatible with the active
progress mode, and where the application programmer is unable or
unwilling to recode to use the appropriate SHMEM wait primitive.
For compliance to a SHMEM standard that has a passive progress
requirement.
Environment Variables
list the environment variables that are currently provided by the SHMEM
run time library.
NOTE
The set of supported environment variables and their defaults may
vary
.
from release to release.
Table 6-1. SHMEM Run Time Library Environment Variables
Environment Variable
Default
Description
$SHMEM_SHMALLOC_INIT_SIZE
16MB
Initial size of the global shared memory
segment.
$SHMEM_SHMALLOC_MAX_SIZE
4GB
Maximum size of the global shared
memory segment.
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: ......