Global Resource Sharing on Workstation and PC Clusters

Our research concerns the design and implementation of algorithms for global resource sharing in workstation clusters. Our first efforts have been in the design and implementation of GMS, a global memory system for a network of workstations. In GMS, global information is used in order to make "globally-optimal," network-wide, page replacement decisions. The system uses idle or "older" pages in the network to house replaced pages from highly active nodes. Thus, on a page fault, a replaced page may be sent to "global memory" rather than to disk. When a page is read from disk and another page must be replaced (sent to disk) in exchange, GMS attempts to replace the "globally least valuable" page in the network.

In our current work, we have extended GMS to include network-wide prefetching. That is, an active node can request that an inactive node prefetch data into the inactive node's memory; the data will then be prefetched just before needed into the active node's memory. Our new version of global memory, including prefetching, is called "PMS" -- Prefetching global Memory System.

We have also experimented with the use of subpages to reduce the latency of remote memory faults, and have conducted analytic modeling of global memory systems to show how server load should be considered in replacement decisions. We have implemented GMS and PMS underneath the virtual memory and file systems on the DEC UNIX operating system, running on an Myrinet-connected network of DEC Alpha workstations. We are now porting to FreeBSD, and will be using a network of Intel PCs and Myrinet switched network. Links to papers on GMS are included below.

Project Members

Hank Levy
Anna Karlin
Geoff Voelker
Mike Feeley (Univ. of British Columbia)
Jeff Chase (Duke University)

Publications

Implementing Global Memory Management in a Workstation Cluster. Michael J. Feeley, William E. Morgan, Frederic H. Pighin, Anna R. Karlin, Henry M. Levy, and Chandramohan A. Thekkath. In Proc. of the 15th ACM Symposium on Operating Systems Principles , December 1995.
Reducing Network Latency Using Subpages in a Global Memory Environment. H.A. Jamrozik, M.J. Feeley, G.M. Voelker, J. Evans II, A.R. Karlin, H.M. Levy, and M.K. Vernon. In Proc. of the Seventh ACM Conference on Architectural Support for Programming Languages and Operating Systems, October 1996. [postscript]
Managing Server Load in Global Memory Systems. Geoffrey Voelker, Herve Jamrozik, Mary Vernon, Henry Levy, and Edward Lazowska. Proc. of the 1997 ACM Sigmetrics Conference on Performance Measurement, Modeling, and Evaluation, June 1997.
Implementing Cooperative Prefetching and Caching in a Global Memory System. Geoff Voelker, Eric Anderson, Tracy Kimbrel, Mike Feeley, Jeff Chase, Anna Karlin, and Henry Levy. Proc. of the 1998 ACM Sigmetrics Conference on Performance Measurement, Modeling, and Evaluation, June 1998.
On the scale and performance of cooperative Web proxy caching. Alec Wolman, Geoff Voelker, Nitin Sharma, Neal Cardwell, Anna Karlin, and Henry Levy. Proc. of the 17th ACM Symp. on Operating Systems Principles, December 1999.

Theses

Michael J. Feeley, Global Memory Management for Workstation Networks, Department of Computer Science and Engineering, University of Washington, December 1996.