Many common areas of scientific computing (for instance, weather modeling, computational fluid dynamics, earthquake simulations, and scientific visualization) are "out-of-core" -- their data sets are too large for physical memory. Existing techniques for managing memory in these programs are unsatisfactory: explicit I/O has the potential for good performance, but is difficult to use, while paged virtual memory sacrifices performance for usability. Traditional virtual memory implementations also allow out-of-core programs to over-consume memory resources, thus severely degrading the performance of other applications.

This talk presents a new, fully-automatic approach that enables out-of-core applications to explicitly manage their memory requirements by I) prefetching pages that will be needed in the near future, and II) informing the operating system about pages that can be replaced. The application programmer is not required to modify source code. Brown's approach unites the ability of the compiler to analyze data access patterns statically and automatically transform code (by inserting the required memory management hints) with the ability of the operating system to monitor dynamic resource usage. A new run-time layer intercepts the hints inserted by the compiler and uses the dynamic information to decide when action needs to be taken. Brown will describe implementation of this system, and present some of performance results which demonstrate that her technique can dramatically improve the performance of array-based out-of-core programs (over implementations that rely on paged virtual memory). She will also show that the negative impact on an interactive application can be virtually eliminated using this approach.

Wednesday, March 14th @ 4pm in DH 1064

A reception will follow in DH 3092.

About Angela Demke Brown

Angela Demke Brown is a Ph.D. candidate in the Computer Science Department at Carnegie Mellon University. She received a B.Sc. degree from York University in 1994, and an M.Sc. degree from the University of Toronto in 1997. Her research interests include resource management, operating systems, compiler optimization, and run-time adaptation.

Angela Demke Brown is a faculty candidate.