Title
VPC prediction: reducing the cost of indirect branches via hardware-based dynamic devirtualization
Abstract
Indirect branches have become increasingly common in modular programs written in modern object-oriented languages and virtual machine based runtime systems. Unfortunately, the prediction accuracy of indirect branches has not improved as much as that of conditional branches. Furthermore, previously proposed indirect branch predictors usually require a significant amount of extra hardware storage and complexity, which makes them less attractive to implement. This paper proposes a new technique for handling indirect branches, called Virtual Program Counter (VPC) prediction. The key idea of VPC prediction is to treat a single indirect branch as multiple virtual conditional branches in hardware for prediction purposes. Our technique predicts each of the virtual conditional branches using the existing conditional branch prediction hardware. Thus, no separate storage structure is required for predicting indirect branch targets. Our evaluation shows that VPC prediction improves average performance by 26.7% compared to a commonly-used branch target buffer based predictor on 12 indirect branch intensive applications. VPC prediction achieves the performance improvement provided by at least a 12KB (and usually a 192KB) tagged target cache predictor on half of the examined applications. We show that VPC prediction can be used with any existing conditional branch prediction mechanism and that the accuracy of VPC prediction improves when a more accurate conditional branch predictor is used.
Year
DOI
Venue
2007
10.1145/1250662.1250715
Proceedings of the 40th Annual International Symposium on Computer Architecture
Keywords
Field
DocType
object oriented language,branch prediction,virtual functions,branch target buffer,virtual machine,program counter
Indirect branch,Virtual machine,Cache,Computer science,Parallel computing,Program counter,Branch target predictor,Real-time computing,Virtual function,Computer hardware,Branch predictor,Performance improvement
Conference
Volume
Issue
ISSN
35
2
0163-5964
Citations 
PageRank 
References 
26
0.86
29
Authors
6
Name
Order
Citations
PageRank
Hyesoon Kim1149381.05
José A. Joao22679.43
Onur Mutlu39446357.40
Chang Joo Lee450615.30
Yale N. Patt54947566.20
Robert Cohn633131.29