The MIXED Procedure

PERFORMANCE Statement

PERFORMANCE < performance-options> ;

The PERFORMANCE statement defines performance parameters for multithreaded computing in solving large mixed model equations and other large matrix sweep operations.

You can specify the following performance-options in the PERFORMANCE statement:

CPUCOUNT=ACTUAL | num

specifies how many processors the procedure assumes to be available on the machine. You can specify any integer from 1 to 256 for num. CPUCOUNT=ACTUAL is equivalent to setting num to be the number of physical processors available. This number can be less than the physical number of CPUs if the SAS process has been restricted by system administration tools. Setting CPUCOUNT= to a number greater than the actual number of available CPUs might result in reduced performance. This option overrides the CPUCOUNT= SAS system option.

NTHREADS=n

specifies the number of threads for analytic computations and overrides the SAS system option THREADS | NOTHREADS. If you do not specify the NTHREADS= option, the number of threads are determined based on the number of CPUs on the machine by creating one thread per CPU for the analytic computations. The largest number that can be specified for n is 256.

By default, PROC MIXED executes in multiple concurrent threads unless you specify the NOTHREADS system option or you force single-threaded execution with NTHREADS=1 or the NOTHREADS options in the PERFORMANCE statement.

THREADS=YES | NO

specifies whether PROC MIXED executes in multiple concurrent threads. The default is YES.

NOTHREAD

turns off the multithreaded computation.