ATI Stream Computing OpenCL Programming Guide - CiteSeerX

ATI STREAM COMPUTINGCompute DevicePrivate Memory(Reg Files)Private Memory(Reg Files) m12. . .Compute Unit nPrivate Memory(Reg Files) 1. . .Private Memory(Reg Files) mProc. Elem.(ALU)Proc. Elem.(ALU)Local Mem.(LDS) 12R/OL1W/OCompute Unit 1atomicR/WColor Buffer. . .ALUProc. Elem.(ALU)Local Mem.(LDS) nProc. Elem.(ALU)read onlyL1Color Bufferwrite onlyatomic read / writeIMAGE / CONSTANT DATA CACHE (L2)(read-only)Compute DeviceMemory(VRAM)GLOBAL MEMORYCONSTANT MEMORYDMAHostPCIeFigure 1.7Interrelationship of Memory DomainsFigure 1.8 illustrates the standard dataflow between host (CPU) and GPU.HOSTPCIeGLOBALLOCALPRIVATEFigure 1.8Dataflow between Host and GPUThere are two ways to copy data from the host to the GPU compute devicememory:• Implicitly by using clEnqueueMapBuffer and clEnqueueUnMapMemObject.• Explicitly through clEnqueueReadBuffer and clEnqueueWriteBuffer(clEnqueueReadImage, clEnqueueWriteImage.).1.4 Memory Architecture and Access 1-11Copyright © 2010 Advanced Micro Devices, Inc. All rights reserved.