Title
Fast Ranking with Additive Ensembles of Oblivious and Non-Oblivious Regression Trees.
Abstract
Learning-to-Rank models based on additive ensembles of regression trees have been proven to be very effective for scoring query results returned by large-scale Web search engines. Unfortunately, the computational cost of scoring thousands of candidate documents by traversing large ensembles of trees is high. Thus, several works have investigated solutions aimed at improving the efficiency of document scoring by exploiting advanced features of modern CPUs and memory hierarchies. In this article, we present QuickScorer, a new algorithm that adopts a novel cache-efficient representation of a given tree ensemble, performs an interleaved traversal by means of fast bitwise operations, and supports ensembles of oblivious trees. An extensive and detailed test assessment is conducted on two standard Learning-to-Rank datasets and on a novel very large dataset we made publicly available for conducting significant efficiency tests. The experiments show unprecedented speedups over the best state-of-the-art baselines ranging from 1.9 × to 6.6 × . The analysis of low-level profiling traces shows that QuickScorer efficiency is due to its cache-aware approach in terms of both data layout and access patterns and to a control flow that entails very low branch mis-prediction rates.
Year
DOI
Venue
2016
10.1145/2987380
ACM Transactions on Information Systems (TOIS)
Keywords
Field
DocType
Learning to rank,additive ensembles of regression trees,document scoring,efficiency,cache-awareness
Data mining,Learning to rank,Search engine,Tree traversal,Bitwise operation,Ranking,Profiling (computer programming),Computer science,Control flow,Theoretical computer science,Ranging
Journal
Volume
Issue
ISSN
35
2
1046-8188
Citations 
PageRank 
References 
12
0.57
18
Authors
7
Name
Order
Citations
PageRank
Domenico Dato1120.57
Claudio Lucchese2110473.76
Franco Maria Nardini331436.52
Salvatore Orlando41595202.29
Raffaele Perego51471108.91
Nicola Tonellotto637739.90
Rossano Venturini743531.07