How changes in computer architecture are
about to impact everyone in the IT business.
BY maRK oSKin
COMPUTER ARCHITECTURE research is undergoing
a renewed vitality. no longer is the road ahead clear
for microprocessors. indeed, a decade ago the road
seemed straightforward: deeper pipelines, more
complex microprocessors, and little change to the
core instruction set architecture. no longer. for a
variety of technological reasons, manufacturers
have embraced multicore Cpus for the mainstream
of desktop computing. such a change represents
the biggest single risk these vendors have taken
in decades, as they are now expecting software
developers to embrace a programming model they
have been reluctant to target in the past.
In this article I look back on computer
architecture research over the past 10
years, including what accounted for this
change and what will happen because
of it. In addition, I survey the field of
computer architecture research, looking at what types of problems we once
thought were important to explore and
how those problems are exacerbated or
mitigated in the future.
Seven years ago, when I started as
a young assistant professor, my computer science colleagues felt computer
architecture was a solved problem.
Words like “incremental” and “
narrow” were often used to describe research under way in the field. In some
ways, who could blame them? To a
software developer, the hardware/software interface—the very core of the
computer architecture research field—
had remained unchanged for most of
their professional lifetimes. Even the
key microarchitectural innovations
(pipelining, branch prediction, caching, and others) appeared to be created
long ago. From the perspective of the
rest of computer science, architecture
was a solved problem. This perception of computer architecture research
had some very real consequences.
NSF folded the computer architecture
(CSA) program together with a grab bag
of areas from VLSI to graphics into an
omnibus “computing processes and
artifacts” cluster. Large-scale DARPA
programs to fund innovative architecture research in academia have recently wound down.
Around 2000, I would also characterize the collective mood of researchers in computer architecture
as overly self-critical and bored of
examining certain core topics in the
field. The outside perspective of computer architecture had become the
inside one. We would bemoan our
field, nicknaming our premier technical conference as the “International
Symposium on Cache Architecture,”
instead of its true title “Computer Architecture.” We amusingly called our
own innovations “yet another” 12 take
on an old problem.