Choosing a DSP: Intel x86, Power Architecture or GPU?
October 13, 2014 | BY: Marc Couture
Multiple dimensions are involved in choosing the right digital signal processor (DSP) solution for a military-aerospace application. Just as you wouldn't build a car with all iron or all aluminum, you typically won't build an embedded processing system with only one type of digital signal processor (DSP).
The main players in DSP - Intel x86, Power Architecture and GPUs - all process floating point data with good precision and dynamic range. And you'll often find combinations of these in systems, with each playing to its strengths.
Power Architecture and Intel x86 both have vector engines, enabling them to execute operations on multiple pieces of data in one clock cycle. The Power Architecture's AltiVec is a 128-bit vector unit, while Intel's AVX is 256-bits wide.
In many systems, a GPU complements the operation of an Intel processor. Like a field programmable gate array (FPGA), a GPU can perform parallel operations with hundreds and sometimes thousands of floating point units. The GPU operates as an accelerator that continually feeds data-intensive applications, such as imaging enhancement and mosaicking, which stitches together input from multiple sensors.
On SWaP-constrained military platforms, such as UAVs, a single GPU can sometimes replace multiple Intel processors to save space and reduce weight and power. In contrast, some processors are ruled out for such environments due to high power needs.
A radical development in DSP is Intel's incorporation of GPUs within the processor die, decreasing latency and making unnecessary the high-speed signaling required between the processor and GPU in typical systems where the processor and GPU are separate, discreet units. Now, developers of electronic warfare systems can consider these processors. Before, they were often restricted to working with FPGAs.
Other factors, besides processing capability and application requirements, also play into processor choice.
- Program longevity is a key consideration for program managers. Their concern is whether parts will be available when a program enters full production. Vendors vary in how long they maintain processor parts. Intel guarantees at least a seven-year supply and Freescale keeps Power Architecture parts for 15 years. GPU vendors typically do not maintain parts for the long term, though companies like Curtiss-Wright arrange for long-term storage of parts that insures their availability.
- A similar consideration is whether code is portable from one generation of a processing technology to the next. Intel x86 and Power Architecture have a track record of supporting cross generation code portability.
- Another factor that influences DSP choice is simply an engineering group's experience with a platform. For instance, they may be comfortable working with Power Architecture or have significant code that was developed on Intel, and are reluctant to change.
With so many issues to consider when choosing a DSP, it makes sense to get expert help. Contact a Curtiss-Wright representative to help you find the right processors to meet the requirements of your application.