The THREADS system option
enables some legacy SAS processes that are thread-enabled to take
advantage of multiple CPUs by threading the processing and I/O operations.
Threading the processing and I/O operations achieves a degree of
parallelism that generally reduces the real time to completion for
a given operation at the possible cost of additional CPU resources.
In SAS 9 and SAS 9.1, the thread-enabled processes include
-
-
Base SAS procedures: SORT, SUMMARY,
MEANS, REPORT, TABULATE, and SQL
-
SAS/STAT procedures: GLM, LOESS,
REG, ROBUSTREG.
For example, in some
cases, processing small data sets, SAS might determine to use a single-threaded
operation.
Set this option to NOTHREADS
to achieve SAS behavior most compatible with releases before to SAS
9, if you find that threading does not improve performance or if threading
might be related to an unexplainable problem. See the specific documentation
for each product to determine whether it has functionality that is
enabled by the THREADS option.