Pages: pp. 5-6
Trends in CMOS technology point to an era of high-performance microprocessor design in which problems such as power consumption and cooling, device- and chip-level variability, and hard and soft errors threaten to slow down historically established performance growth rates. One approach is to add more hardware to separately control each of these threatening technological trends. Let's examine this approach more explicitly. In such a design, you could use the following mechanisms to mitigate the adverse effects:
Each of these hardware mechanisms requires additional area and verification cost; and, often, one approach can adversely affect another dimension of the overall problem. For example, dynamic power management increases the variability of the on-chip power supply voltage, due to increased inductive noise. This increases the susceptibility to timing and soft errors. Similarly, redundancy and recovery support to enhance error tolerance would cause an increase in chip power consumption.
The need for an integrated approach in designing future microprocessors is therefore paramount. First, the management of mutually conflicting optimization goals requires the use of a consolidated monitor-and-control system to detect application and environmental changes, and take appropriate action. Second, designs must employ software support, wherever possible, to simplify the area and power complexity of hardware controls. This means that the compiler and operating system must play an increasingly important role in the scheduling and control of on-chip hardware resources.
I posit a view, therefore, that the future of high-performance, multicore microprocessors promises to herald a new era of system-on-chip designs with integrated hardware-software elements. Early-stage integrated modeling methodologies are a key aspect of this new design era. As such, the new generation of microprocessor designs will require significant investment in presilicon design, analysis, and verification tools, many of which will require key new inventions. Thus, the future promises to be one that poses significant new challenges to computer architects, designers, compiler experts, systems software, and presilicon modelers. However, not withstanding the availability of a new generation of sophisticated toolsets, an integrated design team consisting of experts in individual domains that also have breadth to communicate and work at ease with other experts will be the overarching need of the era.
In this special "Future Trends" issue of IEEE Micro, you will find a series of interesting articles from some of the leading experts and visionaries in the field. I hope the microprocessor and microsystems R&D community will be able to draw from the ideas and opinions expressed in these articles to further accelerate and enhance the race to find integrated, efficient solutions to combat the obstacles posed by future CMOS technologies.