TITLE: Perspectives on the Memory Wall

ABSTRACT:
In 1995, Bill Wulf and Sally McKee published a short paper with the
provocative title: "Hitting the Memory Wall: Implications of the Obvious".
Since that time, the phrase "memory wall" has become part of the lexicon
in high performance computing, but a precise definition remains elusive.
By more clearly differentiating bandwidth and latency concerns, one can
develop simple performance models which will serve to illustrate the
sometimes unexpected ways in which computer designers have (so far)
avoided running into "the wall". Looking forward, it is clear that the
"memory wall" has already become a first-order concern in system
architecture forhigh performance computing, but several potential paths
around the wall can be envisioned and will be reviewed.

DATE/TIME/PLACE: February 18, Wednesday, 1:30-2:30 pm, SDSC Auditorium

SPEAKER: John D. McCalpin, Ph.D., IBM Corporation, Austin, TX

ABOUT THE SPEAKER:
Dr. McCalpin has worked in High Performance Computing for 20 years, with a
long-term interest in performance modelling for bandwidth-intensive
applications. He received his Ph.D. in Physical Oceanography, and held a
faculty position in Marine Studies at the University of Delaware from
1990-1996. While performing basic research in computational
geophysicalfluid dynamics, he also developed the STREAM benchmark, which
has become the de facto industry standard tool for measuring sustainable
memory bandwidth. Leaving academia in 1996, McCalpin worked in the
performance engineering and system architecture groups at SGI. In 1999,
McCalpin fled the insane real estate prices of California and returned to
his native Texas, where he now works in IBM's Global Microprocessor
Development group. His current focus is HPC performance for systems based
on IBM's forthcoming POWER5 processor, as well as system architecture and
performance for IBM's PERCS project -- a long-term projected funded by
DARPA to produce systems capable of PFLOPS sustained application
performance by 2010.

John D. McCalpin, Ph.D.
IBM - 11400 Burnet Road, MS 045-3N098
Austin, TX 78758
(512) 838-6167 or IBM tie line 678/6167