Title
Probabilistic counter updates for predictor hysteresis and stratification
Abstract
Hardware counters are a fundamental building block of modern high-performance processors. This paper explores two applications of probabilistic counter updates, in which the output of a pseudo-random number generator decides whether to perform a counter increment or decrement. First, we discuss a probabilistic implementation of counter hysteresis, whereby previously proposed branch confidence and criticality predictors can be reduced in size by factors of 2 and 3, respectively, with negligible impact on performance. Second, we build a frequency stratifier by making increment and decrement probabilities functions of the current counter value. The stratifier enables a 4-bit counter to classify an instruction's Likelihood of Criticality with sufficient accuracy to closely approximate the performance of an unbounded precision classifier Because probabilistic updates are both simple and effective, we believe these ideas hold great promise for immediate use by industry, perhaps enabling the use of structures such as branch confidence predictors which may have previously been viewed as too expensive given their functionality.
Year
DOI
Venue
2006
10.1109/HPCA.2006.1598118
International Symposium on High-Performance Computer Architecture-Proceedings
Keywords
Field
DocType
stratification,pseudo random number generator
Stratification (seeds),Computer science,Parallel computing,Hysteresis,Real-time computing,Criticality,Probabilistic logic,Classifier (linguistics)
Conference
ISSN
Citations 
PageRank 
1530-0897
8
0.58
References 
Authors
14
2
Name
Order
Citations
PageRank
Nicholas Riley1161.55
Craig B. Zilles293294.74