Note: If your dll is an IIS dll, please see Step by step: How to profile an IIS project instead.
The good news is that it is exactly the same procedure as profiling a standard exe.
Basically: let VB Watch instrument and compile your activeX, then exercize it with your usual container application.
Here is it again, with step 2. updated to check about the Retained in memory project option:
In case your dll is Retained in memory (in the VB6 project's options): press the Open VB Watch Control Center... button, goto the General Options tab, and make sure that Disable Retained in memory... is checked.
3. Click the Profile Project... button on the left and browse for your project you wish to profile.
If you do not have a project ready, you can load the following test project: \Program Files\VB Watch 2\Samples\VB6\Profiler Sample\TestProfiler.vbp.
Here is all what happens:
A copy of the project's source code is made in a created subdirectory. All operations will be performed on this copy, not on your original source.
Some template files are added to the project.
The source code is transformed to allow profiling of this project.
The new project is compiled.
4. Exercize your activeX with your usual container application so that it executes the parts you want to profile.
5. Close the container application. Back in the profiler, your session appears in the top left list view. You can now analyze it.