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Network-on-Chip benchmarking workgroup, status update. March 2011, Erno Salminen. OCP-IP NoC Benchmarking workgroup. Outcome since 2007: 2 tool releases, 2 specifications, 5 white papers, and 4 articles in journals and conferences Benchmark aim to answer two basic questions:
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Network-on-Chip benchmarking workgroup, status update March 2011, Erno Salminen
OCP-IP NoC Benchmarking workgroup • Outcome since 2007: • 2 tool releases, 2 specifications, 5 white papers, and 4 articles in journals and conferences • Benchmark aim to answer two basic questions: • NoC developer: What gain does my novel feature bring? • System integrator: Which NoC should I choose and how should I configure it?
Benefits of common benchmarks • Improved sharing and comparison of R&D results • Most contemporary NoC benchmark cases are proprietary • A set of academic, synthetic benchmarks can be shared and used without these limitations • Increased healthy competitiveness between R&D • Standardized metrics and measurement methodologies enable fair comparison • Increased reproducibility of results and commonality for comparative purposes • Accelerated development and analysis • Available input data and hardware models can speed-up the initial design and performance estimation phase. • Better scalability compared to application benchmarks • Synthetic benchmarks are more suitable for benchmarking purposes since they can exhibit properties of particular fixed size application benchmarks, but can scale with system size while still retaining these properties
Recent activities Second release of Transaction Generator SystemC tool for evaluting MP-SoCs and NoCs LPGPL license Includes OCP-IP TLM kit, GUI, and tutorial Released a white paper on how to model DRAM memories Curently investigating a SystemC DRAM model Released a group’s overview document Download the materials from http://www.ocpip.org 4
Workload model for NoC benchmarking • Separated into disctinct parts • Application’s workload – process network annotated with operation counts and transferred data amounts • Mapping – where the application tasks are executed • Computation architecture – processing capability (ops/cycle), transfer capability (DMA or not), communication overhead (context switch, transfer initiation delay) • Benchmarked NoC
Workload creation • We are currently constructing a set of traffic models for TG • Task graph models, distributed as XML • Some are based on our own earlier prjects and some on literature • Applications examples data-parallel video encoding, picture-in-picture, OFDM, UMTS…
White paper released and executable model under construction The majority of traffic flows to/from DRAM memory Total bandwidth requirement 1.3 GByte/s- 10.5 Gbyte/s 8 processing engine types 1,2,4, or 8 DRAMs Video decoding benchmark example
DRAM modeling • DRAM is performance is essential to the whole system, as previous example showed • Our white paper describes a modeling style for DRAMs • Drastic difference between best case and more realistic one (see the figure) • E.g. 99.67% efficiency vs. 44.31%
Near-future activities • Finalize and publish the first set of traffic models • Strive for DRAM SystemC model • Finding more benchmarks and develop tools further • Suggestions are welcome! • Contact admin@ocpip.org