The newly emerging “fail-slow” failures plague both software and hardware where the victim components are still functioning yet with degraded performance. To address this problem, this article presents Perseus , a practical fail-slow detection framework for storage devices. Perseus leverages a light regression-based model to quickly pinpoint and analyze fail-slow failures at the granularity of drives. Within a 10-month close monitoring on 248K drives, Perseus managed to find 304 fail-slow cases. Isolating them can reduce the (node-level) 99.99th tail latency by 48%. We assemble a large-scale fail-slow dataset (including 41K normal drives and 315 verified fail-slow drives) from our production traces, based on which we provide root cause analysis on fail-slow drives covering a variety of ill-implemented scheduling, hardware defects, and environmental factors. We have released the dataset to the public for fail-slow study.

Functional scenario comprehension of screens in Android applications paves the way for Android app development and Android UI testing, especially in automated UI testing and test reuse. On the one hand, the screens of diverse Android applications contain widgets with many combinations. On the other hand, the screens of different scenarios may leverage similar widgets to fulfill the functionalities. Due to the above reasons, scenario comprehension is still hard to be solved by current approaches. In this paper, to fully understand the functionality of each screen, we propose a novel approach that employs Graph Neural Networks (GNN) to classify scenarios leveraging the transitions between screens and other available information of screens altogether. According to the result evaluated on 30 popular applications in the file management category, our approach improves the classification accuracy by at least 6% compared to previous work, demonstrating that GNN can fully utilize the potential relations and dependencies between the transitioned screens.