Poster: Service Polymorphism: Enhancing Web Service Performance by Serving Clients Dissimilarly

Modern applications often invoke web services to access remote data and functionalities. The current service-oriented paradigm is "one-size-fits-all," where App developers expect a single service to deliver satisfying Quality of Service (QoS) to all geographically and temporally dispersed clients. However, our empirical study reveals that despite the pervasive use of CDN and edge computing, many web services deliver significantly varied QoS to different users, resulting in some clients suffering from poor user experience. This paper introduces service polymorphism, a novel software paradigm that serves dispersed clients dissimilarly to improve their perceived QoS. Service polymorphism allows a client to maintain a list of equivalent services and invokes the one that offers the optimal QoS in the invocation context. The main challenge in supporting service polymorphism lies in minimizing the overhead for fine-grained QoS sensing. To address this challenge, we propose an edge-based QoS sharing mechanism that aggregates the context-specific QoS in edge servers, and allows clients to retrieve the QoS from local WiFi Access Points with minimized latency to decide the optimal service. Our evaluation shows that service polymorphism improves QoS significantly for 8 services out of 20, reducing their average latency by 231 ms (45%), tail latency by 80 ms (12%), and error ratio from 0.2% to 0%.