A Study of Branch Prediction and Fetch Policy on

mattednearAI and Robotics

Dec 1, 2013 (3 years and 4 months ago)


A Study of Branch

Prediction and Fetch Policy on
Simultaneous Multithreading Architecture

Ho Lin & Jong
Jiann Shieh


In the present computer architecture, speculation execution is the general and effective
way to handle the branch problem. T
he performance improvement from the speculation
execution relies on the prediction accuracy. However, the simultaneous multithreading
(SMT) architecture that combines hardware features of wide
issue superscalar and
multithreaded architecture to issue instr
uctions from multiple threads each cycle may have
different prediction behavior. Thus features of SMT architecture and branch prediction are
the primary focus of this study. We propose a branch prediction mechanism with biased
branch filter and confidence
estimator to reduce the competition for branch predictor
between thread and classify conditional branches as biased or confident branches. And
then fetch unit that plays an important role in the SMT architecture decides which threads
to fetch instructions
from each cycle according to the information from our proposed

prediction mechanism.

Keywords: Branch Prediction, Simultaneous Multithreading, SMT, Biased Branch Filter,
Confidence Estimator, Fetch Unit.


9th World Multi
Conference on Systemics
, Cybernetics
and Informatics

(WMSCI 2005), Orlando Florida, USA