Isalist is a set of utilities for SPARC systems that enables users to find out which instruction sets are supported on their machines and also to determine which one will perform the best for them. The set of utilities include:
The isalist command, which prints out an ordered list of supported instruction set
The optisa command, which prints out the best instruction set out of this list
A pragmatic interface, which is the equivalent of using the sysinfo system call
Currently there are many variations of the SPARC processor, some of which can be treated as separate instruction sets. An application binary that is compiled for one variation may not run, or may run with performance degradation, or may run normally on a machine implementing a different variation. The Isalist utilities provide a standard interface so users can choose their application binary correctly to obtain maximum performance. For example, a system administrator can write a wrapper script and use the output of isalist and optisa to choose the appropriate binary for a given application.