1. November 2006 SpaceOps 2010 Conference, Huntsville, Alabama By José Feiteirinha, Nuno Sebastião Date: 25-30 April 2010 Emulation Using the CellBE Processor

2. Purpose Introduction History and Motivation Emulation Techniques –Interpretation –Dynamic Translation The CellBE Processor –Architecture µLeon –Implementation Details –Performance Evaluation Conclusions Agenda

3. Purpose

4. Emulation of Onboard Software is in the Critical Path for SpaceCraft Simulators Heavily explored area Optimization techniques have been here for years now CellBE provides a new processor architecture design It’s performance as an emulator host should be considered Purpose

5. History and Motivation Performance of the new Leon2 processor is 3x to 5x higher than what traditional emulation techniques provide Previous studies have shown that modern emulation technologies can provide enough performance to emulate future space capable processors [PMarques 2006] Computer industry is providing more and more cores per CPU without many gains in the performance of individual cores Operation multi domain missions still require one computer per spacecraft simulator (i.e. increasing costs) Determinism and lateral application behavior are enemies

6. Emulation Techniques

7. Emulation Techniques - Interpretation Interpretation is the most common (and simple) emulation technique

8. Emulation Techniques - Interpretation Interpretation is also the slowest way to emulate

9. Emulation Techniques – Dynamic Translation Dynamic translation improves by blocking and writing into the host memory translated code in the host’s own instruction set

10. The Cell Processor

11. The CellBE Processor - Architecture One “Main” core – PPE – Power Processing Element Multiple “Side” cores – SPEs – Synergetic Processing Elements Operating System

12. µLeon

13. µLeon, a sub-set of the Leon2 processor ModuleLeon2 µ Leon Integer UnitSPARC Compliant Equivalent to 30% of the SPARC ISA Floating PointCo-ProcessorBuilt-in as part of the ISA Registers Windows8 windows of 32 registers Single register window UARTSTwo UARTSSingle state UART TimersTwo timers and one watchdog. n/a Imaginary processor composed of the critical requirements for evaluating the emulation of the real Leon2 processor

14. Performance Results Performance is lower than cutting edge processors

15. Performance Results Near deterministic behaviour

16. Conclusions

17. Conclusion CellBE provides lower throughput for emulation when compared to modern x86 based computers Commonly used architectures have high variance in performance and require the use of thresholds to ensure performance consistency CellBE provides a near deterministic platform for emulation Future processors with similar achitectures should be considered

18. Questions and Answers ? THANK YOU Paulo Marques: pmarques@dei.uc.ptpmarques@dei.uc.pt Damiano Guerrucci: damiano.guerrucci@esa.intdamiano.guerrucci@esa.int

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