User guide
6–SHMEM Description and Configuration
Environment Variables
6-14 IB0054606-02 A
$SHMEM_SHMALLOC_CHECK on Shared memory consistency checks
set for 0 to disable and 1 to enable.
These are good checks for correctness
but degrade the performance of shmal-
loc() and shfree(). These routines are
usually not important for benchmark
performance, so for now the checks are
turned on to catch bugs early.
$SHMEM_IDENTIFY If set, each SHMEM process will print
out the SHMEM identity string and the
path to the SHMEM library file.
$SHMEM_GET_REQ_LIMIT 64 Maximum number of outstanding short
get requests for this end-point for the
short get protocol (0 means unlimited).
Each short get request can be up to
2KB.
$SHMEM_GET_LONG_REQ_LIMIT 16 Maximum number of outstanding get
requests for this end-point for the long
get protocol (0 means unlimited).
$SHMEM_PUT_FRAG_LIMIT 4096 Maximum number of outstanding put
fragments for this end-point for the
short put protocol (0 means unlimited).
Each short put fragment can be up to
2KB.
$SHMEM_PUT_LONG_FRAG_LIMIT 128 Maximum number of outstanding put
fragment requests for this end-point for
the long get protocol (0 means unlim-
ited).
$SHMEM_GET_LONG_SIZE 8KB for
non-blocking
gets
32KB for
blocking
gets
Gets of this size and larger use the
SHMEM long get message protocol.
Note that the parameter only allows the
size to be changed in unison for both
non-blocking and blocking gets.
$SHMEM_PUT_LONG_SIZE 8KB for
non-blocking
puts
16KB for
blocking puts
Puts of this size and larger use the
SHMEM long put message protocol.
Note that the parameter only allows the
size to be changed in unison for both
non-blocking and blocking puts.
Table 6-1. SHMEM Run Time Library Environment Variables (Continued)
Environment Variable Default Description