Yao Yue

Converged Networks Group, IBM China Research Laboratory, Beijing, China
Internship in Performance Evaluation and Optimization of SIP-based Applications on IBM Java Virtual Machine (Modeling and Experimentation over Test Bed)

Motive: Despite their security advantage and development convenience, performance of servers running SIP-based applications on top of Java virtual machine (JVM) are often questioned, mainly due to the impact of GC. The basic GC policy in IBM JVM can be summarized as a stop-the-world mark-sweep-and-compact strategy. Consequently, GC introduces periodical slow response intervals and message loss.

Goal: 1. To streamline servers specifically for SIP-based applications by tuning a number of JVM policies, such as generational GC, concurrent marking and JVM parameters. 2. Calculate performance degradation curves of an optimized server configuration assuming certain user behavior, and point out the inflection point of performance.

Contribution: A series of experiments over test bed with various JVM settings have been deployed and analyzed. So far, we are able to decide optimal policy configurations under different traffic patterns. A deterministic Petri Net model has also been developed to plot performance degradation curves and to predict the inflection point.

Department of Computer Science and Technology, Tsinghua University, China
Graduate Research Assistant in Enhance unstructured P2P system in Privacy and Security, a joint program with Microsoft Research Asia

Motive: While P2P systems have an edge in scalability, they are often quested about their fairness, privacy and security. On the other hand, efficiency, fairness and survivability are interwoven in many P2P file sharing systems such as BitTorrent. Therefore it is important to realize the inter-dependency of performance indices before introducing systems enhancement into such applications.

Goal: 1. To point out the how different aspects, such as fairness, survivability, efficiency and etc., are related to each other. 2. With a deep understanding of BitTorrent like networks acquired in preliminary research, put forward an improved design to enhance security and privacy in BitTorrent like file sharing systems. 3. Provide measurement tools to collect end-to-end performance metrics at low communication cost for a global view of P2P systems.

Contribution: Our preliminary research on takes a modeling approach on the dynamic behavior of BitTorrent like networks. The model reveals how fairness and survivability of a P2P file sharing system are related to the more traditional issues like scalability and efficiency. After realizing our first goal, an enhanced interconnecting mechanism has been designed and partially implemented to improve security and privacy, and this mechanism could be applied to general P2P file-sharing systems. Since achieving high security and privacy can often be contradictory, our scheme supports flexible adaptation when a compromise is required. In addition, a measurement tool to study E2E performance and topology is under development to facilitate experiments on P2P applications.

Advisor: Professor and Department Head Chuang Lin

Department of Computer Science and Technology, Tsinghua University, China

Graduate Research Assistant in Intel IXA University Program (www.ixaedu.com)

Motive: The functionality and performance of many network security applications rely on an ef-ficient, flexible implementation of cryptographic algorithms on network processors (NPs), especially on data plane (fast path). Necessity of benchmarking cryptographic algorithms on NPs rises in the face of rigid hardware solutions and unclear performance of software-based solutions.

Goal: 1. Implementing popular, representative cryptographic algorithms on network processors, with our focus on data-plane. 2. Benchmarking NPs to locate performance bottlenecks. 3. To alleviate the bottlenecks with generic or model-specific optimizations.

Contribution: A major developer of NPCryptBench, a cryptographic benchmark suite for network processors. By applying the benchmarks on several NP models we obtain first-hand statistics. With these data performance bottlenecks under different workloads and system configurations are successfully located. Summarized benchmark methodology and optimization guidelines from both software and architecture angles.

Advisor: Professor and Department Head Chuang Lin

State Key Laboratory of Intelligent Technology and Systems, Department of Computer Science and Technology, Tsinghua University, China

Undergraduate research in Decision Theory and Multi-agent Systems

This is a two semester discussion group/seminar whose members study the classical papers on decision theory and game theory used in multi-agent systems. At the end of each semester, I concluded the seminar with a survey essay. I also presented an introductory talk of multi-agent systems to my classmates and a short course in game theory to my graduate colleagues.

Advisor: Professor Mingsheng Ying and Assistant Professor Sanjiang Li