Hard real-time applications written in Python should not rely on the
cyclic garbage collector. They should call gc.disable at startup, and
completely rely on reference counting for releasing memory. Doing so
might require rewrites to the application, explicitly breaking cycles so
that reference counting can release them.

Even with cyclic gc disabled, applications worried about meeting hard
deadlines need to look even more into memory allocation and
deallocation; e.g. releasing a single object may cause a chained release
of many objects, which can affect worst case execution times. There are
more issues to consider (which are all out of scope of the bug tracker).