1. Opening Up Automatic Structural Design Space Exploration by Fixing Modular Simulation VEERLE DESMET SYLVAIN GIRBAL OLIVIER TEMAM Ghent University Thales TRT INRIA

2. Motivation 2 Veerle Desmet – Sylvain Girbal – Olivier Temam 6th HiPEAC Industrial Workshop – Thales Nov 26th, 2008 [MICRO 2004, Gracia-Pérez et al.] Need for systematic quantitative comparison Need for systematic quantitative comparison

3. Computer Architecture Research 3 Veerle Desmet – Sylvain Girbal – Olivier Temam 6th HiPEAC Industrial Workshop – Thales Nov 26th, 2008

4. Design space exploration: need more than intuition and experience? 4 Time-to-market Veerle Desmet – Sylvain Girbal – Olivier Temam 6th HiPEAC Industrial Workshop – Thales Nov 26th, 2008 area power execution time Multi-objectives

5. ArchExplorer: repository + automatic exploration 5 archexplorer.org database simulation cluster upload daily update pick design points add results test Veerle Desmet – Sylvain Girbal – Olivier Temam 6th HiPEAC Industrial Workshop – Thales Nov 26th, 2008 Server-side InfrastructureWebsite FULLY AUTOMATIC

6. How to compare? 1.Custom simulator 2.Hardware compatibility 3.Software compatibility 4.Upload 6 Veerle Desmet – Sylvain Girbal – Olivier Temam 6th HiPEAC Industrial Workshop – Thales Nov 26th, 2008 Wrapped Simulator & Parameter ranges Custom Simulator DL1 CPU D SM EXWBCM M F $TLB $ $ $ MEM DSEXWBCM M F SM IL1BP L2 S MEM

7. Hardware compatibility 7 Instruction caches Data caches Branch predictors Interconnects Main memory Accelerators... Veerle Desmet – Sylvain Girbal – Olivier Temam 6th HiPEAC Industrial Workshop – Thales Nov 26th, 2008

8. Software compatibility 8 Veerle Desmet – Sylvain Girbal – Olivier Temam 6th HiPEAC Industrial Workshop – Thales Nov 26th, 2008 Isolate the hardware block, possibly by from centralized control to distributed control

9. Software compatibility 9 Veerle Desmet – Sylvain Girbal – Olivier Temam 6th HiPEAC Industrial Workshop – Thales Nov 26th, 2008 Self-Configuration and parameters legality Models of computation Wrapping in SystemC-based on UNISIM communication layer

10. Case study Memory sub-system for embedded processor PowerPC405 8 different cache modules available Complex hierarchies automatically explored Ranking designs for performance, power, energy, area,... Victim Cache Timekeeping Victim cache Stride Prefetcher Content-Directed Prefetcher Stride + Content Directed Prefetcher Tag Prefetcher Global History Prefetcher Skewed associtiative cache 10 Veerle Desmet – Sylvain Girbal – Olivier Temam 6th HiPEAC Industrial Workshop – Thales Nov 26th, 2008

11. Accurate comparison needs compiler tuning as well 11 Veerle Desmet – Sylvain Girbal – Olivier Temam 6th HiPEAC Industrial Workshop – Thales Nov 26th, 2008 1.23 2.62 1.09

12. Best data cache mechanisms per area 12 Veerle Desmet – Sylvain Girbal – Olivier Temam 6th HiPEAC Industrial Workshop – Thales Nov 26th, 2008 CONCLUSIONS: 1.Contrast to Gracia-Pérez et al. [MICRO 2004] 2.No clear winner 3.Close to tuned parametric cache

13. Best data cache mechanisms per area 13 Veerle Desmet – Sylvain Girbal – Olivier Temam 6th HiPEAC Industrial Workshop – Thales Nov 26th, 2008 CONCLUSIONS: 1.Contrast to Gracia-Pérez et al. [MICRO 2004] 2.No clear winner 3.Close to tuned parametric cache

14. Composing cache hierarchies 14 Veerle Desmet – Sylvain Girbal – Olivier Temam 6th HiPEAC Industrial Workshop – Thales Nov 26th, 2008

15. Speedup and Energy Improvement 15 Veerle Desmet – Sylvain Girbal – Olivier Temam 6th HiPEAC Industrial Workshop – Thales Nov 26th, 2008

16. ARCHEXPLORER.ORG Check out this website: 16 Veerle Desmet – Sylvain Girbal – Olivier Temam 6th HiPEAC Industrial Workshop – Thales Nov 26th, 2008

17. 17 Veerle Desmet – Sylvain Girbal – Olivier Temam 6th HiPEAC Industrial Workshop – Thales Nov 26th, 2008

18. Conclusion Permanent open competition(s) Future: superscalar processor branch predictor repository multi-cores Open for your ideas! NoC, compiler extensions,... 18 Veerle Desmet – Sylvain Girbal – Olivier Temam 6th HiPEAC Industrial Workshop – Thales Nov 26th, 2008

19. ARCHEXPLORER.ORG Check out this website: 19 Veerle Desmet – Sylvain Girbal – Olivier Temam 6th HiPEAC Industrial Workshop – Thales Nov 26th, 2008

20. Opening Up Automatic Structural Design Space Exploration by Fixing Modular Simulation VEERLE DESMET SYLVAIN GIRBAL OLIVIER TEMAM Ghent University Thales TRT INRIA