Reconfigurable ECO Cells for Timing Closure and IR Drop Minimization
TIMING CLOSURE IN SYSTEM-ON-CHIP ERA Sam Appleton, CEO CONFIDENTIAL.
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Transcript of TIMING CLOSURE IN SYSTEM-ON-CHIP ERA Sam Appleton, CEO CONFIDENTIAL.
![Page 1: TIMING CLOSURE IN SYSTEM-ON-CHIP ERA Sam Appleton, CEO CONFIDENTIAL.](https://reader035.fdocuments.in/reader035/viewer/2022062313/56649cc25503460f9498a98e/html5/thumbnails/1.jpg)
TIMING CLOSURE IN SYSTEM-ON-CHIP ERA
Sam Appleton, CEO
CONFIDENTIAL
![Page 2: TIMING CLOSURE IN SYSTEM-ON-CHIP ERA Sam Appleton, CEO CONFIDENTIAL.](https://reader035.fdocuments.in/reader035/viewer/2022062313/56649cc25503460f9498a98e/html5/thumbnails/2.jpg)
Challenges in SDC Creation & Verification
It can get a bit messy
“IP”/block level timing
• Making sure design is fully constrained
• Finding balance between timing exceptions and risk
• Verification of timing environment
“SoC/Chip level” timing
• integrating IP
• Ensuring Hierarchical Consistency
• Debugging Macro-Scale problems
• Size & Complexity
![Page 3: TIMING CLOSURE IN SYSTEM-ON-CHIP ERA Sam Appleton, CEO CONFIDENTIAL.](https://reader035.fdocuments.in/reader035/viewer/2022062313/56649cc25503460f9498a98e/html5/thumbnails/3.jpg)
IP level timing closure
It’s a balancing act!“Minimal SDC”
• constrain all functional paths for correctness
• over all modes
• don’t use any exceptions
• minimal case analysis
• minimal clock definitions
• conservative clock groups
“Relaxed SDC”
• static path/mode exceptions added
• one SDC per design mode
• structural/formal MCPs and False Paths
• Clock/Data exceptions
• Use clocks to break up timing domains
![Page 4: TIMING CLOSURE IN SYSTEM-ON-CHIP ERA Sam Appleton, CEO CONFIDENTIAL.](https://reader035.fdocuments.in/reader035/viewer/2022062313/56649cc25503460f9498a98e/html5/thumbnails/4.jpg)
The Balancing Act
Low-RiskHardest Timing, More Power & Area
Higher RiskEasiest Timing, Less Power & Area
1. Find set of timing relaxations that help meet timing goals
2. Ignore all other “available” relaxations that don’t help
3. Allow for reuse of results from previous uses of IP
![Page 5: TIMING CLOSURE IN SYSTEM-ON-CHIP ERA Sam Appleton, CEO CONFIDENTIAL.](https://reader035.fdocuments.in/reader035/viewer/2022062313/56649cc25503460f9498a98e/html5/thumbnails/5.jpg)
The Verification Problem
• “Timing domain” Verification– Debugging clocks, case, modes,
conflicts– Ensure STA treatment is correct– Automating manual debug previously
done with STA
• Functional Verification– For exceptions, functional coverage is
needed– Simulation OR formal (or both)– Critical problem in signoff of timing
environment
![Page 6: TIMING CLOSURE IN SYSTEM-ON-CHIP ERA Sam Appleton, CEO CONFIDENTIAL.](https://reader035.fdocuments.in/reader035/viewer/2022062313/56649cc25503460f9498a98e/html5/thumbnails/6.jpg)
SoC Integration
• Size/Scale– 20-700M instances– 200-3000 clocks– 20-250 IP blocks– 20-200k timing exceptions– 2 or 3 levels of hierarchy– 10000s of lines of scripting– Usually GL netlist
New Level of Complexity and Scale
![Page 7: TIMING CLOSURE IN SYSTEM-ON-CHIP ERA Sam Appleton, CEO CONFIDENTIAL.](https://reader035.fdocuments.in/reader035/viewer/2022062313/56649cc25503460f9498a98e/html5/thumbnails/7.jpg)
SoC Integration Challenges
• Leverage IP timing SDCs
• Make sure SoC is consistent with IPs
• Add toplevel constraints, make sure consistent with IPs
![Page 8: TIMING CLOSURE IN SYSTEM-ON-CHIP ERA Sam Appleton, CEO CONFIDENTIAL.](https://reader035.fdocuments.in/reader035/viewer/2022062313/56649cc25503460f9498a98e/html5/thumbnails/8.jpg)
SoC/IP Consistency
• Critical for Hierarchical Flows
• Heavy use of ETMs for TAT at toplevel make this more critical
• Multiple causes of silicon failure
• Clocks• Case Analysis• Exceptions• Boundary Budget
![Page 9: TIMING CLOSURE IN SYSTEM-ON-CHIP ERA Sam Appleton, CEO CONFIDENTIAL.](https://reader035.fdocuments.in/reader035/viewer/2022062313/56649cc25503460f9498a98e/html5/thumbnails/9.jpg)
Future Directions
• Closing the gap between timing and functional verification– Big need to make sure the timing specification is
functionally verified– SDCs are just like any other manually-created input– Finding optimal exceptions to aid in timing closure
• SoC integration and analysis– Bigger, more complex SoCs– Big need for hierarchical analysis and consistency tools,
that can aid with promotion & demotion of SDCs