Taipei Embedded Outreach OpenCL DSP Profile Proposals

Transcription

1 Copyright 2018 The Khronos Group Inc. Page 1 Taipei Embedded Outreach OpenCL DSP Profile Proposals Prof. Jenq-Kuen Lee, NTHU Taipei, January 2018

2 Copyright 2018 The Khronos Group Inc. Page 2 Outline Speaker Vita OpenCL DSP Profile Proposal Reference Designs and Use Cases Current Status with OpenCL Roadmap

3 Copyright 2018 The Khronos Group Inc. Page 3 Prof. Jenq-Kuen Lee, NTHU Our group contributed to PoCL-based OpenCL runtime on HSA - Codes contributed to HSA Foundation GitHub - also up-streamed to PoCL Prototyping OpenCL compiler (based on Open64) for PAC DSP multi-cores - ESTIMedia 2013, ICPP EMS 2012, ACM TODAES 2015 Compiler optimizations for OpenCL programs - Vector Data Flow Analysis for SIMD Optimizations on OpenCL Programs (Concurrency and Computation: Practice and Experience, 2016) - Pointer-based Divergence for OpenCL(CPC 2013) - Compilers for OpenCL with Affine Registers on GPGPU (ACM TODAES 2017) DSP compiler optimizations (PAC DSP Compiler) - SIMD Intrisinc supports for VLIW DSP (CPC 2010) - PALF: compiler supports for distributed register files in VLIW DSP (Concurrency and Computation: Practice and Experience 2007) Contribute OpenCL DSP Profile Proposals - Funding support from Taiwan MOST and Mediatek

4 Copyright 2018 The Khronos Group Inc. Page 4 Outline Speaker Vita OpenCL DSP Profile Proposal Reference Designs and Use Cases Current Status with OpenCL Roadmap

5 L: K C O

6 OpenCL Research with HSA Architectures w w Enable OpenCL framework on HSA platform Use pocl as our basic OpenCL framework Extend pocl to support HSA platforms by lowering OpenCL APIs to HSA runtime APIs Our enhanced PoCL-based OpenCL runtime for HSA is officially released on HSA Foundation. Upstream to PoCL ml/hsa_status.html (acknowledge our work) J. System Architecture Nov (OpenCL 2.0 Runtime) 6

7 Support heterogeneous computing for OpenCL among CPU, GPU, DSP, and FPGA. Previously, OpenCL is mainly for CPU and GPU Low-power numerical precision to work with vision applications, deep learning applications, and signal processing applications Energy savings up to 35% in the memory energy and the computation of low-power DSP numerics in the OpenCL DSP proposal only consumes 1/7 energy of floating point in hardware. Optional stoachastic rounding mode benefits deep learning applications Demonstrate reference design for Khronos SPIR-V extension with our DSP proposals.

8 Copyright 2018 The Khronos Group Inc. Page 8 Proposals to Khronos OpenCL DSP Profile Goal is to integrate CPU/GPU/DSP - Houston f2f Seattle f2f Frankfurt f2f Seoul f2f Vancouver f2f Amsterdam f2f Chicago f2f 2017 Contributors: - NTHU: C. C. Yang, M. Y. Hsu, S. C. Wang, C Li, Y. Chang, BS Lu, S. Chien, T. Chen - MediaTek: PeiChia Lin, Cheng-Wei Chen, Trent Lo, Diana Chen The proposals are in collaboration with MediaTek

9 Comparison Math Functions Support for Fixed-Point Types Functions Trigonometric Xilinx HLS *bit-width specification cos, cospi sin sinpi *ap_fixed<w,2> where W<=32 Khronos OpenCL C++ proposal cos, sin, tan, acos, asin, atan Hyperbolic None cosh, sinh, tanh, acosh, asinh, atanh Exponential and Logarithmic Power exp *ap_fixed<16,8> and ap_fixed<8,4> sqrt *ap_fixed<w,i> where W<=32 exp, log, log10 pow, sqrt ISO C++ proposal (John) cos, sin None (Tentative) Others None None abs Other Fixed-Point Types Comparisons Support Xilinx HLS Khronos OpenCL C++ proposal exp pow, sqrt ISO C++ proposal (John) ISO C++ proposal (Lawrence) ISO C++ proposal (Lawrence) System C System C Console IO Yes No No No Yes Fixed Point Width Arbitrary DSP: 8, 16, 32 FPGA: Arbitrary Courtesy of Ronan Keryell and Lin-Ya Yu Copyright 2017 Xilinx. 8, 16, 32, 64 - sc_fxval: arbitrary width and binary point location, limited-precision fixed-point: 53

10 Copyright 2018 The Khronos Group Inc. Page 10 Outline Speaker Vita OpenCL DSP Profile Proposal Reference Designs and Use Cases Current Status with OpenCL Roadmap

11 Copyright 2018 The Khronos Group Inc. - Page 11 SPIR-V Ecosystem GLSL HLSL Khronos has open sourced these tools and translators Third party kernel and shader languages glslang MSL HLSL GLSL SPIR-V Cross OpenCL C Front-end OpenCL C++ Front-end SPIR-V Khronos defined and controlled cross-api intermediate language Native support for graphics and parallel constructs 32-bit Word Stream Extensible and easily parsed Retains data object and control flow information for effective code generation and translation SPIR-V (Dis)Assembler SPIR-V Validator Other Intermediate Forms IHV Driver Runtimes LLVM to SPIR-V Bi-directional Translator LLVM Khronos coordinating liaison with Clang/LLVM Community E.g. discussing SPIR-V as supported Clang target

12 Overview Revision of Khronos LLVM IR to SPIRV Convertor on GitHub Example: New Opcode Type: OpTypeFixedPoint 12

13 Example: New Opcode Type - OpTypeFixedPoint OpTypeFixedPoint Declares a new fixed-point type. Width is the bit width of significant digits(significand). Exponent is the absolute value(i.e abs()) of the exponent value Result <id> Literal Number Width Literal Number Exponent... 13

14 Copyright 2018 The Khronos Group Inc. Page 14 OpenCL as Language/Library Backend C++ based Neural network framework Language for image processing and computational photography MulticoreWare open source project on Bitbucket Single Source C++ Programming for OpenCL Open source software library for machine learning Vision processing open source project Compiler directives for Fortran, C and C++ Open compiler for AI framework

15 Use Case: Fixed Point on Tensorflow Tensorflo w Eigen ViennaCL OpenCL 2.2 C++ OpenCL C Khronos f2f Meeting, Chicago, 2017

16 Interfacing Tensorflow/Eigen with ViennaCL ViennaCL provides methods for data copying between Eigen and ViennaCL Therefore, we can enable the Tensorflow-to-OpenCL flow by interfacing Tensorflow/Eigen with ViennaCL Application Tensorflow Output Eigen ViennaCL OpenCL Khronos f2f Meeting, Chicago, 2017

17 Khronos f2f Meeting, Chicago, 2017 From:

18 Enable Built-in Kernels in ViennaCL with Our Proposed OpenCL Fixed-Point To enable the flow, we have revised the.hpp header files which generated OpenCL kernels in the following path: ViennaCL-1.x.x/viennacl/linalg/opencl/kernels/ We enable the use case flow to fixed point by: Enable the use of OpenCL C++ kernels in ViennaCL Enable the use of OpenCL C++ kernels with proposed fixed-point in ViennaCL Enable the use of OpenCL C kernels with proposed fixed-point in ViennaCL Khronos f2f Meeting, Chicago, 2017

19 19 Enable Fixed-Point Type Simulation (GPGPUSim) Extend Clang/SPIR-V translator to accommodate fixed-point Opcodes LLVM: Clang: LLVM IR Fixer (or LLVM IR Khronos Adaptor) Fix IR difference Kernel Identification (Annotation v.s Explicit IR semantic) Special Types Other special IR annotations for NVPTX Add/Map fixed-point ISA extension for NVPTX OpenCL Kernel clang LLVM IR (SPIRV) SPIRV Translator SPIRV SPIRV Translator LLVM IR (SPIRV) LLVM IR Fixer LLVM IR (NVPTX) NVPTX Backend NVPTX

20 Enable SPIR-V to GPGPUSim

21 Copyright 2018 The Khronos Group Inc. Page 21 Outline Speaker Vita OpenCL DSP Profile Proposal Reference Designs and Use Cases Current Status with OpenCL Roadmap

22 Copyright 2018 The Khronos Group Inc. Page 22 OpenCL Next Directions Generalizing DSP Path to DSP, FPGA, Embedded GPU, DL - Incorporate OpenCL DSP Profile Proposals Feature Sets Capability - Allow Code Specializations - Optional features are captured as capability flags in the API Enhance SPIR-V to accommodate OpenCL low-power numerics

23 Copyright 2018 The Khronos Group Inc. Page 23 Suggestions and Comments We welcome DSP vendors and IP companies for suggestions and inputs We also hope to encourage companies to participate in Khronos activities and the research and design with Khronos APIs!