* ThreadSpotter far surpasses simply collecting raw performance data – instead, it identifies, classifies and instructs the developer in ways to remove specific issues. * ThreadSpotter offers a solid, detailed understanding of performance problems to allow a quick resolution on the system under examination. It also models other execution environments and provides performance optimization guidance for other systems. * ThreadSpotter models thread communication and interaction effects, giving advice on how to resolve the resulting performance issues.

* Xdebug's basic functions include the display of stack traces on error conditions, maximum nesting level protection and time tracking. * The debug information that Xdebug can provide includes the following: - stack and function traces in error messages with: - full parameter display for user defined functions - function name, file name and line indications - support for member functions - memory allocation - protection for infinite recursions * Xdebug also provides: - profiling information for PHP scripts - code coverage analysis - Capabilities to debug your scripts interactively with a debugger front-end.