Processing Architecture for Power Efficiency and Performance
Arm big.LITTLE technology is a heterogeneous processing architecture that uses up to three types of processors. ”LITTLE” processors are designed for maximum power efficiency, while “big” processors are designed to provide efficient, sustained compute performance.
With three dedicated processors and an expanded envelope for power and area, the big.LITTLE solution can adjust to dynamic usage patterns for smartphones, tablets, and other devices.
big.LITTLE adjusts to periods of high-processing intensity, for instance, in mobile gaming and web browsing. It can also alternate with longer periods of low-processing intensity tasks, such as texting, email and audio, and with quiescent periods for complex apps.
The performance demanded from users of current smartphones and tablets is increasing at a much faster rate than the capacity of batteries or power savings from advances in semiconductor processes. At the same time, users are demanding longer battery life within roughly the same form factor. This conflicting set of demands requires innovations in mobile SoC design beyond those that process technology and traditional power management techniques can deliver.
Typical Processor Combinations
The Arm Cortex-A series processor combinations that meet big.LITTLE requirements are shown below:
Armv9.2 - DynamIQ big.LITTLE - DynamIQ Shared Units-120
- Ultimate-Performance CPU (CXC): Cortex-X4
- Performance-Efficient CPU (big): Cortex-A720
- High-Efficiency CPU (LITTLE): Cortex-A520
Armv9.0 - DynamIQ big.LITTLE - DynamIQ Shared Units-110
- Ultimate-Performance CPU (CXC): Cortex-X2, Cortex-X3
- Performance-Efficient CPU (big): Cortex-A710, Cortex-A715
- High-Efficiency CPU (LITTLE): Cortex-A510
Armv8.2 - DynamIQ big.LITTLE - DynamIQ Shared Units
- Ultimate-Performance CPU (CXC): Cortex-X1
- Performance-Efficient CPU (big): Cortex-A75, Cortex-A76, Cortex-A77, Cortex-A78
- High-Efficiency CPU (LITTLE): Cortex-A55
Armv8.0 - big.LITTLE
Features and Benefits
Arm big.LITTLE processing takes advantage of the variation smart devices require in performance by combining two very different processors in a single SoC.
The big processor is designed for maximum performance within the mobile power budget.
The smaller processor is designed for optimal efficiency and can address all but the most intense periods of work.
big.LITTLE software automatically manages task allocation to the appropriate CPU cores. The operating system is directly aware of the high-performance and high-efficiency cores in the system and can dynamically allocate each task based on required performance.
Includes operating system software to run on the big.LITTLE hardware and full support from the broader Arm ecosystem.
Talk with an Expert
Interested in designing a next-generation mobile device? Talk to an Arm expert about how big.LITTLE technology can help you.
Everything you need to know to make the right decision for your project.