Imperial College London


Faculty of EngineeringDepartment of Computing

Professor of Mathematical Modelling



+44 (0)20 7594 8363p.harrison Website




353Huxley BuildingSouth Kensington Campus





Peter Harrison is Professor of Mathematical Modelling in the Department of Computing at Imperial College London, where he has worked since 1976. He graduated at Christ's College Cambridge as a Wrangler in Mathematics in 1972 and went on to gain Distinction in Part III of the Mathematical Tripos in 1973, winning the Mayhew prize for Applied Mathematics. He has researched into stochastic performance modelling and algebraic program transformation for some thirty five years, visiting IBM Research Centers for two spells.  He has written two books, had over 200 research papers published and chaired the Joint Sigmetrics/Performance conference at Imperial in 2012. The results of his research have been exploited extensively in industry, forming an integral part of Metron's Athene capacity planning tool.  In the early 2000s he developed, and later mechanised, the RCAT methodology, from which new product-forms for Markovian networks have been found by several authors, and pioneered in the modelling of flash storage systems, incorporating dynamic workloads via Hidden Markov Models.  Response time distributions have always been a favourite and are currently being investigated in sharded storage systems, task-replication and energy-saving, using both generating function and matrix analytic methods.

Selected Publications

Journal Articles

Qiu Z, Perez JF, Birke R, et al., 2017, Cutting latency tail: analyzing and validating replication without canceling, Ieee Transactions on Parallel and Distributed Systems, ISSN:1558-2183

Harrison PG, Patel NM, Knottenbelt WJ, et al., 2016, Energy--Performance Trade-Offs via the EP Queue, Acm Transactions on Modeling and Performance Evaluation of Computing Systems, Vol:1, ISSN:2376-3639, Pages:1-31

Osman R, Harrison PG, Osman R, et al., 2015, Approximating closed fork-join queueing networks using product-form stochastic Petri-nets, Journal of Systems and Software, Vol:110, ISSN:0164-1212, Pages:264-278

Qiu Z, Perez JF, Harrison PG, et al., 2015, Beyond the mean in fork-join queues: Efficient approximation for response-time tails, Performance Evaluation, Vol:91, ISSN:0166-5316, Pages:99-116

Balsamo S, Harrison PG, Marin A, et al., 2010, A unifying approach to product-forms in networks with finite capacity constraints, Performance Evaluation Review, Vol:38, ISSN:0163-5999, Pages:25-35

Tsimashenka I, Knottenbelt WJ, Harrison PG, et al., 2016, Controlling variability in split-merge systems and its impact on performance, Annals of Operations Research, Vol:239, ISSN:0254-5330, Pages:569-588

Harrison PG, Marin A, Harrison PG, et al., 2014, Product-Forms in Multi-Way Synchronizations, Computer Journal, Vol:57, ISSN:0010-4620, Pages:1693-1710

Harrison PG, Hayden RA, Knottenbelt WJ, et al., 2013, Product-forms in batch networks: Approximation and asymptotics, Performance Evaluation, Vol:70, ISSN:0166-5316, Pages:822-840

Harrison PG, Harrison SK, Patel NM, et al., 2012, Storage workload modelling by hidden Markov models: Application to Flash memory, Performance Evaluation, Vol:69, ISSN:0166-5316, Pages:17-40

Field AJ, Harrison PG, Field AJ, et al., 2010, BUSY PERIODS IN FLUID QUEUES WITH MULTIPLE EMPTYING INPUT STATES, Journal of Applied Probability, Vol:47, ISSN:0021-9002, Pages:474-497

Harrison P, HARRISON PG, Harrison PG, et al., 1988, Linearisation: An optimisation for nonlinear functional programs, Science of Computer Programming, Vol:10, ISSN:0167-6423, Pages:281-318


HARRISON PG, KHOSHNEVISAN H, Harrison PG, et al., 1992, A NEW APPROACH TO RECURSION REMOVAL, Theoretical Computer Science, Vol:93, ISSN:0304-3975, Pages:91-113

Harrison, P.G., Pitel, E., HARRISON PG, et al., 1995, Response time distributions in tandem G-networks, Journal of Applied Probability, Vol:32, ISSN:0021-9002, Pages:224-246

Field, A.J., Harrison, P.G., Field, A.J., et al., 1999, Sojourn Times in a Random Queue With and Without Preemption,, European Journal of Operational Research, Vol:112, ISSN:0377-2217, Pages:646-653

Harrison PG, Harrison PG, Harrison PG, et al., 2004, Compositional reversed Markov processes, with applications to G-networks, Performance Evaluation, Vol:57, ISSN:0166-5316, Pages:379-408

HARRISON PG, REEVE MJ, Harrison PG, et al., 1987, THE PARALLEL GRAPH REDUCTION MACHINE, ALICE, Lecture Notes in Bioinformatics, Vol:279, ISSN:0302-9743, Pages:181-202

Harrison, P.G., Strulo, B., Harrison PG, et al., 2000, SPADES-a Process Algebra for Discrete Event Simulation, Journal of Logic and Computation, Vol:10, ISSN:0955-792X, Pages:3-42

Harrison PG, Harrison PG, Harrison PG, et al., 2009, Product-forms and functional rates, Performance Evaluation, Vol:66, ISSN:0166-5316, Pages:660-663

Dingle NJ, Harrison PG, Knottenbelt WJ, et al., 2004, Uniformization and hypergraph partitioning for the distributed computation of response time in very large Markov models, Journal of Parallel and Distributed Computing, Vol:64, ISSN:0743-7315, Pages:908-920


Harrison, P.G., Harrison PG, Harrison PG, et al., 1999, On teaching M/G/1 theory with extension to priority queues, IEE Proceedings-Computers and Digital Techniques, Vol:147, ISSN:1350-2387, Pages:23-26

HARRISON PG, KHOSHNEVISAN H, Harrison PG, et al., 1992, ON THE SYNTHESIS OF FUNCTION INVERSES, Acta Informatica, Vol:29, ISSN:0001-5903, Pages:211-239

Harrison, P.G., Knottenbelt, W.J., 2002, Passage time distributions in large markov chains, Performance Evaluation Review, Vol:30, ISSN:0163-5999, Pages:77-85

HARRISON PG, Harrison PG, 1981, TRANSIENT-BEHAVIOR OF QUEUING-NETWORKS, Journal of Applied Probability, Vol:18, ISSN:0021-9002, Pages:482-490

HARRISON PG, PITEL E, 1993, SOJOURN TIMES IN SINGLE-SERVER QUEUES WITH NEGATIVE CUSTOMERS, Journal of Applied Probability, Vol:30, ISSN:0021-9002, Pages:943-963

DEGUZMAN IP, HARRISON PG, MEDINA E, et al., 1993, PIPELINES FOR DIVIDE-AND-CONQUER FUNCTIONS, Computer Journal, Vol:36, ISSN:0010-4620, Pages:254-268

Harrison PG, Harrison PG, Harrison PG, et al., 2003, Turning back time in Markovian process algebra, Theoretical Computer Science, Vol:290, ISSN:0304-3975, Pages:1947-1986

Bennett AJ, Field AJ, Harrison PG, et al., 1996, Modelling and Validation of Shared Memory Coherency Protocols., Perform. Eval., Vol:27/28, Pages:541-563


Chis TS, Harrison PG, 2016, Performance-energy trade-offs in smartphones, Pages:127-135

Qiu Z, Perez JF, Harrison PG, et al., 2016, Tackling Latency via Replication in Distributed Systems, 7th ACM/SPEC International Conference on Performance Engineering (ICPE), ASSOC COMPUTING MACHINERY, Pages:197-208

Harrison PG, Qiu Z, Harrison PG, et al., 2013, Performance enhancement by means of task replication, 10th European Performance Engineering Workshop (EPEW2013), Pages:191-205, ISSN:0302-9743

Balsamo S, Harrison PG, Marin A, et al., 2010, A Unifying Approach to Product-forms in Networks with Finite Capacity Constraints, 2010 ACM SIGMETRICS International Conference on Measurement and Modeling of Computer Systems, ASSOC COMPUTING MACHINERY, Pages:25-35

Jones GL, Harrison PG, Harder U, et al., 2011, Fluid queue models of battery life, MASCOTS 2011, IEEE Computer Society, Pages:278-285, ISSN:1526-7539

Harrison, P.G., Zatschler, H., Harrison PG, et al., 2004, Sojourn time distributions in modulated G-queues with batch processing, 1st international conference on the quantitative evaluation of systems (QEST 2004), Enschede, Netherlands, IEEE Computer Soc, Los Alamitos, Pages:90-99

Harrison, P.G., Knottenbelt, W.J., 1999, Distributed disk-based solution techniques for large Markov models, Proc 3rd Int. Conference on the Numerical Solution of Markov Chains, NSMC 99, Zaragoza

Harrison PG, Zhang Y, Harrison PG, et al., 2005, Delay analysis of priority queues with modulated traffic, 13th IEEE International Symposium on Modeling, Analysis and Simulation of Computer and Telecommunication Systems, IEEE COMPUTER SOC, Pages:280-287, ISSN:1526-7539

Harrison, P.G., Knottenbelt, W.J., Harrison PG, et al., 2000, Passage Time Distributions in Large Markov Chains, IFIP Working Group 7.3 & University of Central Florida Symposium on Advanced Performance Modeling (SAPM), Orlando, Florida, ACM, Pages:77-85, ISSN:0163-5999

More Publications