[Starpu-devel] AMD Fusion: post-full-utilization computing?

[Chris Hennick <christopherhe@trentu.ca>]

On the Fusion Trinity APUs coming out late this year, full utilization of both the CPU and GPU won't be possible. Instead, each will have the same TDP as the entire chip, and they'll both run at partial power to process mixed workloads. So says Phil Rogers, lead architect on AMD's Heterogeneous System Architecture, who spoke with me yesterday at a workshop in Toronto. 

Will StarPU be able to properly schedule Fusion APUs that have this power trade-off? AMD claims it will make software load-balancing unnecessary, but apparently there's still a performance benefit to using both the CPU and GPU at once, and I suspect that there may still be a few tasks whose CPU/GPU preference is weak enough that adaptive provisioning is still worthwhile.

This is the first instance I've seen of a chip having a power/cooling bottleneck by design, but I'm now convinced that power and cooling have displaced processing hardware as the limiting resource in computing, just as processing hardware displaced RAM capacity in the 90s. Trinity's power scaling seems like a sensible design decision on that basis, but it suggests to me that far more disruptive changes are in store given the increasing abundance of transistors and scarcity of power.

Sincerely,
Chris Hennick

Trent University

Peterborough, ON, Canada

http://softwetware.blogspot.com/