Monitoring the Debug Information
The information on a debugging session is displayed in the dedicated tabs of the Debug tool window named after the selected run/debug configuration.
When displaying and modifying local variables or watches values, PhpStorm uses the Default Encoding setting for the current project or the IDE encoding if no encoding is specified at the project level. The same setting is used when showing the PHP console script output.
User-defined constants are grouped under a separate Constants node which is by default collapsed. Once expanded or collapsed, the Constants node preserves this state across the debugging sessions. This means that is you expand or collapse the node, stop or complete the current debugging session, and then start a new one, the node is shown as it was during the previous debugging session, that is, expanded or collapsed respectively.
Monitor debugger overhead
The debug process is part of the runtime and, therefore, may impact performance. Every evaluation of an expression, or stepping over the code use the same memory as the debugged application, and may cause large overhead.
PhpStorm lets you view this overhead so that you can quickly detect what causes it and reduce it by removing unnecessary breakpoints, disabling automatic evaluation of expressions, turning off async stacktraces, etc.
To invoke the Overhead pane, click the icon in the top-right corner of the Debug tool window: