The Data Center’s Secret Weapon: FPGA Acceleration

1. FPGA

FPGA, whose full name is Field-Programmable Gate Array, is a type of semiconductor device that contains configurable logic blocks and interconnections and can be programmed to implement various digital circuits.

FPGAs are often compared to ASICs and microcontrollers. ASICs are designed for specific tasks and are optimized for performance, but lack flexibility. Microcontrollers are general-purpose devices, usually used for simple tasks and controlled by software.

The advantage of FPGA is that it can adapt to various tasks while maintaining high performance. FPGAs are dynamically reconfigurable, making them ideal for applications requiring flexibility and rapid development.

FPGA includes the following components:

1. Logic block

Logic blocks are the basic units of FPGAs and contain programmable logic elements that can be configured to perform different digital functions such as AND, OR and XOR gates. Define the functions and connections of logic blocks through programming to implement the required digital circuits.

Programmability of logic blocks is a key feature of FPGAs, providing a high degree of flexibility and customizability.

2. Interconnection

Interconnects are the "wires" that connect logical blocks together. It forms a programmable routing matrix, supports flexible connections between different logic blocks, and ultimately defines the functions of the FPGA.

3. Input/output block

Input/output (I/O) blocks enable the FPGA to communicate with external devices such as sensors, switches, or other integrated circuits. Configurable to support various voltage levels, standards and protocols.

4. Configuration memory

Configuration memory stores programming data that defines how the FPGA's logic blocks and interconnects are configured. These data are loaded during power-up so that they can perform predetermined functions.

2. Why is FPGA faster than CPU and GPU?

Both CPU and GPU adopt von Neumann structure to execute instructions and share memory. The fundamental reason why FPGA is faster than CPU and GPU is that it does not use instruction set architecture and shared memory architecture.

In the Feng structure, the execution unit needs to be able to execute arbitrary instructions, so it requires instruction memory, decoders, arithmetic units for different instructions, and branch jump processing logic. In FPGA, the function of the logic unit is determined during reprogramming without instructions.

Memory in Feng's architecture serves two purposes: 1) saving state, and 2) processing communication between units. FPGA's registers and on-chip memory (BRAM) belong to their own control logic, eliminating unnecessary arbitration and caching.

In FPGA, the connection between a logic unit and surrounding logic units is determined during reprogramming, and no shared memory communication is required. For pipeline computing tasks, FPGA's pipeline parallelism and data parallelism have obvious advantages and can achieve lower latency.

In the data center, the main advantage of FPGA is low latency, suitable for streaming computing-intensive and communication-intensive tasks. Compared with CPU and GPU, FPGA is more stable and has excellent performance. Although ASIC performs well in terms of throughput, latency, power consumption, etc., its research and development costs are high and the cycle is long, and it is not as flexible as FPGA to adapt to the needs of various scenarios. In multi-tenant environments in data centers, the use of FPGAs can maintain homogeneity and simplify task scheduling and operation and maintenance.

In summary, FPGA has excellent performance and stability when processing streaming computing-intensive and communication-intensive tasks, giving it broad application prospects in data centers and other fields.