Distinguished Guest Lecturer

What Analytical Performance Modeling Teaches Us About Computer Systems Design

Mor Harchol-Balter
Computer Science Dept.
Carnegie Mellon University

Sep 26 2007 3:30 pm
480 Dreese Labs
All interested parties are invited to attend.
Refreshments will be served in the lecture room.

Abstract:

Computer systems design is based on many commonly-held beliefs and heuristics, many of which have never been challenged:

Thousands of server farm "load balancing" policies do exactly that -- they aim to balance the load among the servers. But is load balancing necessarily a good thing?
Consider a choice between a single machine with speed s, and n identical machines with speed s/n. Which would you choose?
Scheduling policies which favor "short" jobs, like Shortest-Remaining-Processing-Time-First (SRPT) are often avoided because it is feared that they starve the "long" jobs. But does favoring "short" jobs necessarily hurt "long" ones?
Cycle stealing between a "donor" machine and a "beneficiary" machine is a central theme in distributed systems. The donor machine helps the beneficiary machine with jobs, whenever the load at the donor machine is below some threshold. But why are we giving the donor machine all the control?

In this talk, we will consider these and other fundamental questions in system design and look at how new research in analytical performance modeling helps us overturn some age-old beliefs.

Bio:

Mor Harchol-Balter is an Associate Professor of Computer Science at Carnegie Mellon University. She received her doctorate from the Computer Science department at the University of California at Berkeley under the direction of Manuel Blum. She is a recipient of the McCandless Chair, the NSF CAREER award, the NSF Postdoctoral Fellowship in the Mathematical Sciences, multiple best paper awards, and several teaching awards, including the Herbert A. Simon Award for Teaching Excellence. She currently serves as Treasurer of the SIGMETRICS board, and Program Chair for SIGMETRICS 2007 and for QEST 2007.

Host: Bettina Bair