1. Fast FPGA Resource Estimation Paul Schumacher & Pradip Jha Xilinx, Inc.

2. Outline  Motivations  Estimation Details  Results, Examples, & Demo  Conclusions & Future Improvements

3. The Need for More Information Logic Utilization: Number of Slice Flip Flops: 301 out of 12,288 2% Number of 4 input LUTs: 900 out of 12,288 7% Logic Distribution: Number of occupied Slices: 498 out of 6,144 8% Total Number 4 input LUTs: 920 out of 12,288 7% Number used as logic: 900 Number used as a route-thru: 20 Number of bonded IOBs: 21 out of 320 6% Number of BUFG/BUFGCTRLs: 1 out of 32 3% Number used as BUFGs: 1 Number used as BUFGCTRLs: 0 Total equivalent gate count for design: 8,944 How are these resources being used?!? Virtex®-6 FPGA ®

4. Exemplary FPGA Design Flow HLL Definition Optimization RTL Generation Synthesis & Simulation Constraints met? Place & Route Y N FPGA Bitstream  Issue #1: Perspective –Overlook vast design space from high level –Your implementation: very low level –You need to deftly navigate both levels  Issue #2: Time –Designing can be very iterative process –Performing what if scenarios can be costly –Possible tradeoffs: speed vs. accuracy

5. Exemplary FPGA Design Flow High-Level Estimation HLL Definition Optimization RTL Generation Synthesis & Simulation Constraints met? Place & Route Y N FPGA Bitstream  In-depth information –Supply perspective desired by designers –Provide context: where, when, why  Immediate feedback –Offer quick estimations –Increasing benefits with multiple runs

6. What Do We Have?  Provides estimated FPGA resources of RTL designs –Without running synthesis –All resources reported –All FPGA families supported  Benefits –Fast: 100x faster than synthesis –Accurate: 15.2% average error –Transparent: in default RTL flow –Useful: help user select part, etc.  Released with ISE ® 11 PlanAhead™

7. Resource Estimation Tool Flow  User-provided input –RTL source code –Settings (e.g., FPGA family) –Tcl script (batch mode)  Obtain netlist from HDL parser/elaborator  Estimate each macro in netlist  Refine using synthesis modeling  Estimation output –Interactive database (GUI) –Report files (XML, Excel) HDL Source Code Library Characterization HDL Parser/Elaborator Design Netlist Macro-Level Estimations Refinements Estimation Database PlanAhead Tool

8. Benchmark Results FPGA Resource Post-Map Estimation Error (Avg.)* Slices15.2% LUTs15.6% Flip-Flops11.5% BlockRAMs6.4% DSP48s2.2% Run-Time**17.2 sec * Using suite of 100 customer designs across three FPGA families ** Run-time includes HDL parser/elaborator + estimation

9. Estimation Run-Time

10. Demo: MPEG-4 Decoder

11. PlanAhead Integration Resources by Function Resources by Hierarchy

12. Results: MPEG-4 Decoder FPGA Family Comparison Memory Comparison Both experiments performed in less than one minute! QCIF CIF 4CIF 720p 1080p

13. Estimation Use Models  Early in design: immediate feedback  Later in design: “hot spot” identification  Design space exploration (DSE)  Increased abstraction level  Design benchmarking & comparison

14. Conclusions  Resource estimator integrated into PlanAhead  Provides detailed analysis of design –Breakdown of resources by functionality & hierarchy –Statistics on memories and bit widths  Future releases –Improved QoR –Estimation of other requested design budgets –Integration with other tools  Contact us with any questions! –Email: {paul.schumacher, pradip.jha}@xilinx.com