homepage

Version: 2.7.4 (and any prior 2.7-version. not tested with 3.x)
Compiler: VS 2008 Professional
If I compile Python using the batch 
> PCbuild\build_pgo.bat -2
Visual Studio fails to correctly collect profile information for the project "python27.dll". As a result, no real optimisation takes place.
The command "build_pgo.bat -2" runs the full test suite (..\lib\test\regrtest.py) to collect profile data. Experiments show, that several test cases (i.e. test_os and test_subprocess) break the collection of profile data. Probably the failure is related to the creation of sub-processes. I consider it a Visual Studio bug.
To work around this issue I created a list of good test cases and patched build_pgo.bat to run only the tests from this list.

See also #21907.

I think I'd rather see a blacklist than a whitelist; it should be much shorter and can be passed to regrtest with the "-x" option within build_pgo.bat.
Since we officially discourage PGO with VS 2008 and 2010 (due to compiler bugs) anyway, marking this as low priority.

It's indeed a very low priority issue.
You mention VS2008 and VS2010 PGO compiler bugs. I'm aware of the VS 2010 bugs, but I didn't observe any VS 2008 PGO bug with Python 2.7. Are you aware of any publicly available bug reports?
About the black/white list. I started with a black list, but then I switched to a white list for the following reason: the goal of running the test suite is to generate a reasonable profile. It is not a goal to test anything. Therefore both white list and black listing is possible.
I consider it more likely that a newly added test breaks the PGO build than that an existing test will be modified in a breaking way. Therefore I consider the while list superior for this particular application.
But as you already stated, it is low prio.