Toward More Energy-Efficient Datacenters with Enhanced Programmable Silicon

在半导体芯片上制造更多晶体管的能力使更多的计算成为可能，通过无处不在的通信、先进的医学成像、按需娱乐交付等改变了社会。我们已经习惯了计算的成本和能量随着时间的推移呈指数级下降，从而实现了新的应用程序和社会效益，从而推动了对进一步提高计算能力的投资。这种良性循环现在正受到威胁，因为随着传统处理器(CPU)制造的改进，计算所需的能量不再充分下降。还有一种选择：将专用硬件配置到现场可编程门阵列(现场可编程门阵列)芯片中，而不是用软件指令控制通用的CPU硬件。这使得现场可编程门阵列可以使用CPU所需能量的10%或更少来进行许多计算。*然而，现场可编程门阵列也面临着自身的挑战。首先，设计一个在FPGA上运行的应用程序比在CPU上运行更难，而且随着制造工艺的不断改进，不断增加FPGA的逻辑容量，完成充分利用它们的设计变得非常耗时。其次，越来越多的计算正在从通常使用现场可编程门阵列的手机基站等专用系统转移到如今几乎完全使用CPU的集中式数据中心。将计算转移到数据中心可以实现集中管理和硬件共享，但数据中心会消耗大量电力(约占美国电力需求的2%)。它们可以极大地受益于现场可编程门阵列的能效，但现场可编程门阵列应用程序设计和应用程序间共享的困难限制了它们在数据中心的使用。*我们将通过创建新的模块化软件工具，让工程师能够轻松连接较小的硬件块来创建完整的应用程序，从而使当今的高容量现场可编程门阵列更易于使用。我们还将研究在FPGA芯片中嵌入通信网络，以使硬件模块更容易进行通信。我们将创建一种新的设计风格，允许随着时间的推移中断应用程序并将其换入和换出FPGA，从而使其可以共享。最后，我们将把一个用于光激活化疗的由现场可编程门阵列加速的模拟器和优化器扩展到数据中心规模，并展示我们的新工具、现场可编程门阵列架构和可交换设计风格如何为这一应用程序带来好处。这将验证我们对现场可编程门阵列的改进，并有助于使一种有前景的新癌症疗法变得实用。*我们提出的创新将使现场可编程门阵列在数据中心得到更广泛的使用，从而降低能源、运营成本和对环境的影响。此外，由于能源是当今计算的限制因素，在数据中心实现更高能效的计算对于进一步扩展计算能力及其带来的新应用和好处至关重要。**

The ability to fabricate ever more transistors on a semiconductor chip has enabled ever more computation, transforming society with ubiquitous communications, advanced medical imaging, on-demand entertainment delivery and more. We have become accustomed to the cost and energy of computation dropping exponentially over time, enabling new applications and societal benefits that motivate investment in raising computational capabilities further. This virtuous cycle is now under threat as the energy required for a computation no longer drops sufficiently with improved manufacturing of conventional processors (CPUs). There is an alternative: configure specialized hardware into Field Programamble Gate Array (FPGA) chips instead of controlling general CPU hardware with software instructions. This allows FPGAs to use 10% or less of the energy required by a CPU for many computations.***However, FPGAs face their own challenges. First, it is harder to design an application to run on an FPGA than on a CPU, and as improved manufacturing continually increases the logic capacity of FPGAs it is becoming very time-consuming to complete designs that fully utilize them. Second, increasingly computation is moving from special purpose systems such as cell phone base stations, which often employ FPGAs, to centralized data centers, which today almost exclusively use CPUs. Moving computation to data centers enables centralized administration and hardware sharing but Data centers consume tremendous amounts of power (~2% of US electricity demand). They could greatly benefit from the energy-efficiency of FPGAs, but the difficulty of FPGA application design and sharing between applications have limited their use in data centers.****We will make today's high-capacity FPGAs easier to use by creating new modular software tools that let engineers easily connect smaller hardware blocks to create a full application. We will also investigate embedding a communication network in the FPGA chip to make it easier still for hardware blocks to communicate. We will create a new design style that allows applications to be interrupted and swapped in and out of an FPGA over time so it can be shared. Finally, we will scale an FPGA-accelerated simulator and optimizer for light-activated chemotherapy to data center scale, and show how our new tools, FPGA architectures and swappable design style benefit this application. This will both validate our FPGA improvements and help make a promising new cancer therapy practical.***Together the innovations we propose will enable wider use of FPGAs in the data center, reducing energy, operating costs and environmental impact. Furthermore, as energy is the limiting factor in computation today, making more energy-efficient computing practical in data centers is essential for further scaling of computational capabilities, and the new applications and benefits it will enable.**