### What this PR does / why we need it? - Add test guidance - Add reduce layer guidance - update faq on determinitic calculation --------- Signed-off-by: MengqingCao <cmq0113@163.com> Signed-off-by: Yikun Jiang <yikunkero@gmail.com> Co-authored-by: Yikun Jiang <yikunkero@gmail.com>