Predicated instructions and multipath execution- Confidence estimation
Confidence estimation is a technique for assessing the quality of a particular prediction.
Applied to branch prediction, a confidence estimator attempts to assess the prediction made by a branch predictor.
A low confidence branch is a branch which frequently changes its branch direction in an irregular way making its outcome hard to predict or even unpredictable.
Four classes possible:
- correctly predicted with high confidence C(HC),
- correctly predicted with low confidence C(LC),
- incorrectly predicted with high confidence I(HC), and
- incorrectly predicted with low confidence I(LC).