Polynomial-Time Verification and Testing of Implementations of the Snapshot Data Structure

We analyze correctness of implementations of the snapshot data structure in terms of linearizability. We show that such implementations can be verified in polynomial time. Additionally, we identify a set of representative executions for testing and show that the correctness of each of these executions can be validated in linear time. These results present a significant speedup considering that verifying linearizability of implementations of concurrent data structures, in general, is EXPSPACE-complete in the number of program-states, and testing linearizability is NP-complete in the length of the tested execution. The crux of our approach is identifying a class of executions, which we call simple, such that a snapshot implementation is linearizable if and only if all of its simple executions are linearizable. We then divide all possible non-linearizable simple executions into three categories and construct a small automaton that recognizes each category. We describe two implementations (one for verification and one for testing) of an automata-based approach that we develop based on this result and an evaluation that demonstrates significant improvements over existing tools. For verification, we show that restricting a state-of-the-art tool to analyzing only simple executions saves resources and allows the analysis of more complex cases. Specifically, restricting attention to simple executions finds bugs in 27 instances, whereas, without this restriction, we were only able to find 14 of the 30 bugs in the instances we examined. We also show that our technique accelerates testing performance significantly. Specifically, our implementation solves the complete set of 900 problems we generated, whereas the state-of-the-art linearizability testing tool solves only 554 problems

Using machine learning to classify test outcomes

When testing software it has been shown that there are substantial benefits to be gained from approaches which exercise unusual or unexplored interactions with a system - techniques such as random testing, fuzzing, and exploratory testing. However, such approaches have a drawback in that the outputs of the tests need to be manually checked for correctness, representing a significant burden for the software engineer. This paper presents a strategy to support the process of identifying which tests have passed or failed by combining clustering and semi-supervised learning. We have shown that by using machine learning it is possible to cluster test cases in such a way that those corresponding to failures concentrate into smaller clusters. Examining the test outcomes in cluster-size order has the effect of prioritising the results: those that are checked early on have a much higher probability of being a failing test. As the software engineer examines the results (and confirms or refutes the initial classification), this information is employed to bootstrap a secondary learner to further improve the accuracy of the classification of the (as yet) unchecked tests. Results from experimenting with a range of systems demonstrate the substantial benefits that can be gained from this strategy, and how remarkably accurate test output classifications can be derived from examining a relatively small proportion of results

LogEvent2vec : LogEvent-to-vector based anomaly detection for large-scale logs in internet of things

Funding: This work was funded by the National Natural Science Foundation of China (Nos. 61802030), the Research Foundation of Education Bureau of Hunan Province, China (No. 19B005), and the International Cooperative Project for “Double First-Class”, CSUST (No. 2018IC24), the open research fund of Key Lab of Broadband Wireless Communication and Sensor Network Technology (Nanjing University of Posts and Telecommunications), Ministry of Education (No. JZNY201905), the Open Research Fund of the Hunan Provincial Key Laboratory of Network Investigational Technology (No. 2018WLZC003). This work was funded by the Researchers Supporting Project No. (RSP-2019/102) King Saud University, Riyadh, Saudi Arabia. Acknowledgments: We thank Researchers Supporting Project No. (RSP-2019/102) King Saud University, Riyadh, Saudi Arabia, for funding this research. We thank Francesco Cauteruccio for proofreading this paper.Peer reviewedPublisher PD