Specifies that SAS use threaded processing if it is available.
Valid in: |
configuration file, SAS invocation, OPTIONS
statement, SAS System Options window
|
Category: |
System administration: Performance
|
PROC OPTIONS GROUP= |
PERFORMANCE
|
-
THREADS
-
specifies to use threaded processing for
SAS applications that support it.
Interaction |
If THREADS is specified
either as a SAS system option or in PROC SORT and another program has the
input SAS data set open for reading, writing, or updating using the SPD engine,
then the procedure might fail and write a subsequent message to the SAS log. |
-
NOTHREADS
-
specifies not to use threaded processing
for running SAS applications that support it.
Interaction: |
When you specify
NOTHREADS, CPUCOUNT= is ignored unless you specify a procedure option that
overrides the NOTHREADS system option. |
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 engine indexing
-
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.
The system option THREADS determines when
threaded processing is in effect. The SAS system option CPUCOUNT= suggests
how many system CPUs are available for use by thread-enabled SAS procedures.
Copyright © 2011 by SAS Institute Inc., Cary, NC, USA. All rights reserved.