DTrace: Dynamic Tracing in Oracle

A. DTrace Tunable Variables

Several tunable variables are available within DTrace for customization when necessary. Many of these variables are named at the DTrace consumer level to facilitate per-consumer modifications (that is, per instance of dtrace(1M) either as a one-liner or as a D script), with a corresponding kernel variable name that will have systemwide scope (affecting every instance of dtrace(1M)). The default values work very well the majority of the time. For the most part, changing the default value can and should be done on a per-consumer basis vs. systemwide. Table A-1 is taken from the “Options and Tunables” chapter of the DTrace Guide,¹ with some additional information, such as the default values on Solaris 10.

Table A-1 DTrace ...