Group Discussion Hong Man 07/21/2010 1

UMD DIF with GNU Radio From Will Plishker’s presentation. 2 GRC The DIF Package (TDP) Platforms GPUs Multi- processors GNU Radio Engine Python/C++ Python Flowgraph (.py) 3a) Perform online scheduling DIF specification (.dif) 3b) Architecture specification (.arch?) CellFPGA XML Flowgraph (.grc) Schedule (.dif,.sched) 4) Architecture aware MP scheduling (assignment, ordering, invocation) Processors Memories Interconnect 1) Convert or generate.dif file (Complete) Platform Retargetable Library Uniprocessor Scheduling Existing or Completed Proposed Legend DIF Lite 2) Execute static schedules from DIF (Complete)

SSP Interface with DIF Currently DIF extracts dataflow model from GRC of GNU radio. – GRC is at the waveform level (component block diagram) To interact with DIF, we need to construct CL models at the waveform level – Our current works are mostly at radio primitive level – We need to start waveform level CL modeling – Open questions: Mapping “things” and “paths” in CL models to “actors” in dataflow models Representing “data rates” (“tokens”) in CL models “Processing delay” is missing in both models 3

Scheduling with Dataflow Models Scheduling based on dataflow models may achieve performance improvement with multi-rate processes ( example from Will Plishker’s presentation ) SDR at physical layer and MAC layer are mostly single-rate processes, and may not see significant performance improvement by using dataflow based scheduling Multicore scheduling is an interesting topic – Currently the assignments of “actors” to processors are done manually 4

GPU and Multicore Our findings on CUDA – Many specialized library functions optimized for GPUs – Parallelization has to be implemented manually – UMD CUDA work (FIR and Turbo decoding) have not been connected to their dataflow work yet Some considerations – Extend our investigation to OpenCL – Focus on CL modeling for multicore systems Automatically parallelize certain common DSP operations (e.g. FIR, FFT) from CL models – Operation recognition and rule-based mapping 5

Next Step Beyond rehosting – optimal code generation – c/c++ → (CL model) → SPIRAL – c/c++ → (CL model) → CUDA or OPEN CL (GPU and multicore) – c/c++ → (CL model) → c/c++ using SSE intrinsics CL modeling tasks – At both primitive level and waveform level – CL modeling from AST – DSP operation (or primitive) recognition – Code segment extraction, validation and transform 6