Computer Systems Performance

The course will introduce the students to the basic methods for analysis of computational & informational systems performance with respect to the requested services. Such systems include multi-core processors, operating systems, cloud systems with virtual machines (data centers), information systems, large databases, computer networks, and all network-centric client-server system over the Internet.

The focus of the course will be on analytical methods from queuing theory and their application in real systems through examples and exercises. It includes introduction to queuing theory, elements of queuing networks (general product-form networks, mean value analysis), techniques based on queuing networks (operational laws, exact and approximate solution algorithms, bounds, hierarchical modeling and special systems analysis techniques), measurement metrics (load, benchmarks, throughput, goodput, etc.). The course will introduce the students to applications of modern systems performance analysis (client-server architectures, Intranets, Internet and Web services). In addition, the course includes analysis of priority queues and basic analysis techniques of closed queuing networks. Finally, the course will introduce the students in the concept and properties of Age-of-Information, which is based on the above principles and it is nowadays used in plenty of application in sensor network systems of the Internet-of-Things.

The course is accompanied by special sessions, where emphasis will be given in practical applications of queuing systems through solving example-cases and exercises.

The outline of the course includes:

• Overview of probability theory, focusing on memoryless distributions of random variables (Poisson and exponential distribution), definitions of Markov stochastic processes, ergodicity and stationarity.
• Definitions and basic queuing prototypes (queuing models), arrival processes, service processes, server utilization, mean queue state and average queuing time, Little’s law, throughput and loss probability.
• Birth-and-death stochastic processes and applications in simple queuing system of Markov nature: M/M/1, M/M/1/K, M/M/N, M/M/N/N.
• Open and closed queuing networks, Burke theorem, Jackson and Gordon/Newel theorem.
• Applications in analysis of performance of data networks (Internet), multi-core processing systems, client-server information systems, query processing systems in large databases, and client service systems, e.g. in banks, tolls, etc.
• Age-of-information in the Internet-of-Things: introduction and analysis.