SAS 9.4 Language Reference, 6th Edition

Definitions for Optimizing System Performance

performance statistics

are measurements of the total input and output operations (I/O), memory, and CPU

time used to process individual DATA steps or PROC steps. You can obtain these

statistics by using SAS system options that can help you to measure your job's initial

performance and to determine how to improve performance.

system performance

is measured by the overall amount of I/O, memory, and CPU time that your system

uses to process SAS programs. By using the techniques discussed in the following

sections, you can reduce or reallocate your usage of these three critical resources to

improve system performance. You might not be able to take advantage of every

technique for every situation, but you can choose the ones that are most appropriate

for a particular situation.

Collecting and Interpreting Performance

Statistics

Using the FULLSTIMER and STIMER System Options

The FULLSTIMER and STIMER system options control the printing of performance

statistics in the SAS log. These options produce different results, depending on your

operating environment. See the SAS documentation for your operating environment for

details about the output that SAS generates for these options.

The following output shows an example of the FULLSTIMER output in the SAS log, as

produced in a UNIX operating environment.

Log 12.1 Sample Results of Using the FULLSTIMER Option in a UNIX Operating

Environment

NOTE: DATA statement used:

real time 0.19 seconds

user cpu time 0.06 seconds

system cpu time 0.01 seconds

Memory 460k

Semaphores exclusive 194 shared 9 contended 0

SAS Task context switches 1 splits 0

The STIMER option reports a subset of the FULLSTIMER statistics. The following

example shows STIMER output in the SAS log.

Log 12.2 Sample Results of Using the STIMER Option in a UNIX Operating Environment

NOTE: DATA statement used:

real time 1.16 seconds

cpu time 0.09 seconds

196 Chapter 12 • Optimizing System Performance