Performance issue in /src/inputs/util.py (by P3)

[DLPerf]

Hello! I've found a performance issue in /src/inputs/util.py: dataset.batch(batch_size)(line 229) should be called before dataset.map(parse_func)(line 224), which could make your program more efficient.

Here is the tensorflow document to support it.

Besides, you need to check the function parse_func called in dataset = dataset.map(parse_func) whether to be affected or not to make the changed code work properly. For example, if parse_func needs data with shape (x, y, z) as its input before fix, it would require data with shape (batch_size, x, y, z) after fix.

Looking forward to your reply. Btw, I am very glad to create a PR to fix it if you are too busy.

[DLPerf]

Hello, I'm looking forward to your reply~