Steve Overton posted this article:

When troubleshooting data performance problems, IO problems, or simple library connectivity, I use a simple snippet of code to push the data storage to the limits.  It is useful because it stresses the data storage component, whether it be a SAS dataset on local file storage or an external database like Oracle, and it provides useful performance metrics.  To make it even better, since this is a SAS Macro it can easily be called multiple times for different libraries by setting the 2 parameters in the %BENCHMARK() macro.

Get the macro here