In the

electronics industry The electronics industry is the industry (economics), industry that produces electronic devices. It emerged in the 20th century and is today one of the largest global industries. Contemporary society uses a vast array of electronic devices that ar ...

, dark silicon is the amount of circuitry of an

integrated circuit An integrated circuit (IC), also known as a microchip or simply chip, is a set of electronic circuits, consisting of various electronic components (such as transistors, resistors, and capacitors) and their interconnections. These components a ...

that cannot be powered-on at the nominal operating voltage for a given thermal design power (TDP) constraint.

Dennard scaling In semiconductor electronics, Dennard scaling, also known as MOSFET scaling, is a scaling law which states roughly that, as transistors get smaller, their power density stays constant, so that the power use stays in proportion with area; both vol ...

would posit that as transistors get smaller, they become more efficient in proportion to the increase in number for a given area, but this scaling has broken down in recent years, meaning that increases in the efficiency of smaller transistors are not proportionate with the increase in their number. This discontinuation of scaling has led to sharp increases in

power density Power density, defined as the amount of power (the time rate of energy transfer) per unit volume, is a critical parameter used across a spectrum of scientific and engineering disciplines. This metric, typically denoted in watts per cubic meter ...

that hamper powering-on all transistors simultaneously while keeping temperatures in a safe operating range. As of 2011, researchers from different groups have projected that, at 8 nm technology nodes, the amount of dark silicon may reach up to 50–80% depending upon the processor architecture, cooling technology, and application workloads. Dark silicon may be unavoidable even in server workloads with abundance of inherent client request-level parallelism.

Challenges and opportunities

The emergence of dark silicon introduces several challenges for the architecture,

electronic design automation Electronic design automation (EDA), also referred to as electronic computer-aided design (ECAD), is a category of software tools for designing Electronics, electronic systems such as integrated circuits and printed circuit boards. The tools wo ...

(EDA), and hardware-software co-design communities. These include the question of how best to utilize the plethora of transistors (with potentially many dark ones) when designing and managing energy-efficient on-chip many-core processors under peak power and thermal constraints. Architects have initiated several efforts to leverage dark silicon in designing application-specific and accelerator-rich architectures. Recently, researchers have explored how dark silicon exposes new challenges and opportunities for the EDA community. In particular, they have demonstrated thermal, reliability (soft error and aging), and process variation concerns for dark silicon many-core processors.

References

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