– that is the only mode available at the moment, correct? The JIT does not quantize (yet?).

yeah, eager mode is the only mode that’s supported in public release, but graph mode is coming up in 1.6 as well.

How does pytorch decide what is “previous”?

PyTorch don’t do this in eager mode. that’s why in eager mode users need to manually place QuantStub and DeQuantStub themselves. this is done automatically in graph mode quantization.
eager mode will just swap all modules that has a qconfig, so user need to make sure the swap makes sense and set qconfig and place QuantStub/DeQuantStub correctly.