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Reducing CPU Time by Using More Memory or Reducing I/O |
Also, because the CPU performs all the processing that is needed to perform an I/O operation, an option or technique that reduces the number of I/O operations can also have a positive effect on CPU usage.
Storing a Compiled Program for Computation-Intensive DATA Steps |
Another technique that can improve CPU performance is to store a DATA step that is executed repeatedly as a compiled program rather than as SAS statements. This is especially true for large DATA step jobs that are not I/O-intensive. For more information on storing compiled DATA steps, see Creating and Executing Stored Compiled DATA Step Programs.
Reducing Search Time for SAS Executable Files |
The PATH= system option specifies the list of directories (or libraries,
in some operating environments) that contain SAS executable files. Your default
configuration file specifies a certain order for these directories. You can
rearrange the directory specifications in the PATH= option so that the most
commonly accessed directories are listed first. Place the least commonly accessed
directories last.
Operating Environment Information:
Specifying Variable Lengths |
Many high performance RISC (Reduced Instruction Set Computer) processors pay a very large performance penalty for movement of unaligned data. When possible, leave numeric data at full width (eight bytes). Note that SAS must widen short numeric data for any arithmetic operation. On the other hand, short numeric data can save both memory and I/O. You must determine which method is most advantageous for your operating environment and situtation.
Note: Alignment can be especially important when you process a data set by
selecting only specific variables or when you use WHERE-expression processing.
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