12:45 PM, January 11, 2001
Packard Electrical Engineering Building, Room 204

Scheduling Your Network Connections

Mor Harchol-Balter,
Computer Science Department,
Carnegie Mellon University

About the talk:

This talk proposes a method for improving the performance of Web servers servicing static HTTP requests. The idea is to give preference to those requests which are quick, or have small remaining processing requirements, in accordance with the SRPT (Shortest-Remaining-Processing-Time) scheduling policy.

The implementation is at the kernel level and involves controlling the order in which socket buffers are drained into the network. Experiments use the Linux operating system and the Flash web server.

Empirical results indicate that SRPT-based scheduling of connections yields significant reductions in mean response time, mean slowdown, and variance in response time at the Web server. Most importantly, and counter to intuition, the large requests are not at all (or hardly) penalized by SRPT-based scheduling.

To explain the above results, we present some of our new theorems on SRPT scheduling under heavy-tailed workloads. These theorems motivate our implementation work.

This research is joint with my students: Nikhil Bansal and Bianca Schroeder.

About the speaker:

Mor Harchol-Balter has been an Assistant Professor at Carnegie Mellon University since 1999. Mor's research involves applying new scheduling theory and queueing theory towards improving the performance of computer systems. Her work spans both analysis and implementation and emphasizes integrating measured workload distributions into the problem solution. She heads the SYNC (Scheduling Your Network Connections) Project at Carnegie Mellon.

More Info:

Powerpoint slides