From MSDN:
The profiler is an analysis tool that you can use to examine the run-time behavior of your programs. By using profiler information, you can determine which sections of your code are working efficiently. The profiler can produce information showing areas of code that are not being executed or that are taking a long time to execute.

But in Visual C++ 6.0, you often found that the profile menu item is grayed. How to enable it?

To enable profile in VC 6.0, you first need to set the correct link parameter, and rebuild all the project.

Wait a minute, do you find that the profile menu item is still grayed?
OK. It’s because that you installed vc6 with one account but use it with another one. It’s mayby a bug of VC6.
But how can you to correct it? It’s easy. Just modify the entry value in the registery.

[HKEY_CURRENT_USER\Software\Microsoft\Devstudio\6.0\General]
“ProfilerInstalled”=dword:00000001