The application behaves differently when it's running with the debugger connected

Symptoms

Application execution time is affected when running under winIDEA with certain debug windows open.

Root cause

Some debug windows (e.g., Watches, Memory, or Special Function Registers) can be configured for Real-time Update. When enabled, winIDEA continuously accesses target CPU resources to refresh data.

If complex or large data structures are being observed, this can significantly impact target execution time.

Solution

1. Close all debug windows in winIDEA.

This makes sure that no background updates are performed.

2. Run the application from the reset state.

This prevents the debugger from accessing target resources during execution and best simulates a standalone target operation. If the problem disappears, one of the previously open debug windows was affecting runtime performance.

3. Reopen debug windows one by one.

After opening each window, run the application again from reset to verify that it still runs properly. This helps identify which window configuration causes the slowdown.

Recommendations

Watches window

• Real-time Update is typically safe for a few simple variables.
• Avoid monitoring large structures. Remove them or disable Real-time Update for that window if needed.

Memory and Special Function Registers windows

• Real-time Update is disabled by default because it can cause heavy target access.
• Enable it only for specific debugging purposes and with full awareness of the potential impact on execution time.

More resources

• Watches window
• Memory window
• Special Function Registers window