Appendix C. Run Time Environment Variables

Table C-1 lists the run time environment variables.

Table C-1. Run Time Environment Variable

Variable

Default

Description

MPC_BLOCKTIME

1000000

Thread wait time before blocking

MPC_BLOCKTYPE

SLEEP

Thread action after waiting (YIELD or SLEEP)

MPC_CHUNK[SIZE]

none

Size of loop chunks

MPC_GANG

ON

Control of gang scheduling (ON or OFF)

MPC_MAX_BLOCKS

64

Maximum control blocks in parallel region

MPC_NUM_THREADS

# CPUs

Number of parallel threads

MPC_SCHEDTYPE

(or INTERLEAVE)

simple

Loop schedule type (SIMPLE, DYNAMIC, GSS,