Write software once and reuse
There is another reason why AMD's move upstream is important.
Software developers want to write once, compile as necessary, run on many platforms and to know that the code they have written can be reused over multiple generations of hardware. The advent of multicore processing risks destroying that situation. The hardware companies have to do something to preserve code portability and that probably means a broad set of standardization issues.
And so AMD is attempting to ease the path of CPU/GPU programming under the Fusion System Architecture intermediate layer, which it calls FSAIL and which it describes as a virtual instruction set architecture. That intermediate layer then calls on the underlying resources, with automated load balancing and dispatch and AMD wants FSA to be able to cope with those resources whether they are x86, ARM, Mali, PowerVR and so on.
But as the eco-system Kool-aid kicked in AMD realized that such a shift in processor ideology is big and more than it could possibly achieve on its own. To make the Fusion System Architecture something worth building it has to offer software developers the broadest possible platform, and guarantees of portability. And who knows more about assembling a broad club of chipmaking partners than ARM.
The question remains – and this Phil Rogers was not laying out for the audience – as to how AMD will make its money out of the Fusion System Architecture.
Is it by being the best implementor of FSA in silicon? This is the historical AMD model in that is has competed with other x86 chip makers. Or is it by licensing the Fusion System Architecture, which is the ARM model? And there is good reason why ARM does not try to compete with its licensees.
Probably AMD will stick to the old fashioned way by making FSA heterogeneous multicore chips. It is in its culture. So they go open and free and ask everyone to come on-board. But don't expect Intel to join in something which acts as a playing-field leveler for the next stage of many-core processor development.
One question asked at the Fusion Developers' Summit which appeared to go unanswered, was whether the FSA could eventually see the CPU and GPU cores merge together into a single building block. It is my interpretation that there was nothing in Phil Rogers presentation that either requires this or prohibits this. But of course a unified CPU/GPU ISA would, at least initially, be a novelty rather than standardized block. But, if a unified logic and graphics core is more power and area efficient then the FSA should allow it to prosper.
Related links and articles:
AMD-authored OpenCL textbook due in August
AMD makes Fusion CPU, GPU agnostic
AMD rolls A series x86, graphics CPUs
Analysis: Why ARM-AMD makes sense
Analyst: AMD-ARM deal makes no sense