株式会社トプスシステムズ

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株式会社トプスシステムズ

  1. 1. Wear-Leveling vs. Write-Performance: Simulation Based Controller Design Deepak Shankar Founder and CEO Mirabilis Design Inc. Mirabilis Design Inc., All rights reserved. Presented in Flash Memory Summit Monday, August 17, 2009
  2. 2. Distribution of Operations  Flash Memory manager • Read, write and erase to Array • ECC, Wear Leveling, Bad block management  Flash Controller • File IO emulation, Managing super blocks • Device Select, address and data routing • Cache and buffer management  Device Manager (USB, SATA, PCIe, etc.) • Routing, protocol conversion  Others Mirabilis Design Inc., All rights reserved. Presented in Flash Memory Summit 2 Monday, August 17, 2009
  3. 3. Growing Complexity of NAND  SLC, MLC, QLC, SLC+MLC+QLC  Application-aware wear leveling  Intelligent file I/O and data management for file type  Geometry shrinks increases the operational issues for ECC, data, data logging and partial page ops  Variable page sizes and interface speeds  Static vs. dynamic wear leveling based on data Mirabilis Design Inc., All rights reserved. Presented in Flash Memory Summit 3 Monday, August 17, 2009
  4. 4. Performance Impact of Controller  Behavior processing • Offloaded to Host CPU or GPU for high speed designs • Multi-core vs. higher processor frequency • Multi-threaded vs. sequential code processing  Software operation • Garbage collection • Multi-level read/Write • Future treads of interrupting Erase  Buffer • Optimal data buffering- Page size per interface or more? • Intelligent data pipelining  Interfaces • Number of Channel, Transfer rates, data and Channel priority Mirabilis Design Inc., All rights reserved. Presented in Flash Memory Summit 4 Monday, August 17, 2009
  5. 5. Power Consideration in designing with Flash and SSD  Most power consumption is in I/O transfer from device to Flash  As array gets larger, leakage is a bigger factor  Control processing is focused on number of processor cores and active scheduling  Lower power supply voltage reduces memory cell power and lowers the operating frequency Mirabilis Design Inc., All rights reserved. Presented in Flash Memory Summit 5 Monday, August 17, 2009
  6. 6. Early Virtual Prototyping to Optimize Controller Design  Software model of the controller  Model generates statistics for • Power (instant, average, battery) • Performance (response time, throughput)  Application Traffic Attributes • Request rate, command sequence, data size, priority, file type, source and destination address  System Level Attributes • Clock speed, Width, processing resource,  Controller Attributes • Cache arbitration, Buffering, Virtual Channels, CrossBar Mirabilis Design Inc., All rights reserved. Presented in Flash Memory Summit 6 Monday, August 17, 2009
  7. 7. Architecture Consideration- Flash-based Consumer Device Mirabilis Design Inc., All rights reserved. Presented in Flash Memory Summit 7 Monday, August 17, 2009
  8. 8. Modeling Statistics- Flash-based Consumer Device Mirabilis Design Inc., All rights reserved. Presented in Flash Memory Summit 8 Monday, August 17, 2009
  9. 9. Architecture Consideration- Hybrid Drives Mirabilis Design Inc., All rights reserved. Presented in Flash Memory Summit 9 Monday, August 17, 2009
  10. 10. Hybrid Drive- Performance Statistics Mirabilis Design Inc., All rights reserved. Presented in Flash Memory Summit 10 Monday, August 17, 2009
  11. 11. Summary  Lots of opportunity for cost, power and performance optimization  Growing complexity requires more architecture studies using software, hardware and system activity  Virtual Prototype can provide visibility into the system operation  Simulation model can be used for designing the software very early in the design cycle Mirabilis Design Inc., All rights reserved. Presented in Flash Memory Summit 11 Monday, August 17, 2009

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