Intel® Quartus® Prime Standard Edition User Guide: Design Optimization

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ID 683230
Date 11/12/2018
Public
Document Table of Contents
Document Table of Contents x
1. Design Optimization Overview 2. Optimizing the Design Netlist 3. Timing Closure and Optimization 4. Area Optimization 5. Analyzing and Optimizing the Design Floorplan 6. Netlist Optimizations and Physical Synthesis 7. Engineering Change Orders with the Chip Planner A. Intel® Quartus® Prime Standard Edition User Guides
1. Design Optimization Overview x
1.1. Device Considerations 1.2. Required Settings for Initial Compilation 1.3. Trade-Offs and Limitations 1.4. Intel® Quartus® Prime Software Tools for Design Optimization 1.5. Design Space Explorer II 1.6. Design Optimization Overview Revision History
1.1. Device Considerations x
1.1.1. Device Migration Considerations
1.2. Required Settings for Initial Compilation x
1.2.1. Guidelines for I/O Assignments 1.2.2. Guidelines for Time Constraints 1.2.3. Partitions and Floorplan Assignments for Incremental Compilation
1.3. Trade-Offs and Limitations x
1.3.1. Preserving Results and Enabling Teamwork 1.3.2. Reducing Area 1.3.3. Reducing Critical Path Delay 1.3.4. Reducing Power Consumption 1.3.5. Reducing Runtime
1.4. Intel® Quartus® Prime Software Tools for Design Optimization x
1.4.1. Design Visualization Tools 1.4.2. Advisors 1.4.3. Design Exploration
1.5. Design Space Explorer II x
1.5.1. How DSE II Works 1.5.2. Performing a Design Exploration with the DSE II Utility
1.5.1. How DSE II Works x
1.5.1.1. Use of Computing Resources 1.5.1.2. Optimization Parameters 1.5.1.3. Result Management
2. Optimizing the Design Netlist x
2.1. When to Use the Netlist Viewers: Analyzing Design Problems 2.2. Intel® Quartus® Prime Design Flow with the Netlist Viewers 2.3. RTL Viewer Overview 2.4. State Machine Viewer Overview 2.5. Technology Map Viewer Overview 2.6. Netlist Viewer User Interface 2.7. Schematic View 2.8. State Machine Viewer 2.9. Cross-Probing to a Source Design File and Other Intel® Quartus® Prime Windows 2.10. Cross-Probing to the Netlist Viewers from Other Intel® Quartus® Prime Windows 2.11. Viewing a Timing Path 2.12. Optimizing the Design Netlist Revision History
2.3. RTL Viewer Overview x
2.3.1. Maximizing Readability in RTL Viewer 2.3.2. Running the RTL Viewer
2.6. Netlist Viewer User Interface x
2.6.1. Netlist Navigator Pane 2.6.2. Properties Pane 2.6.3. Netlist Viewers Find Pane
2.7. Schematic View x
2.7.1. Display Schematics in Multiple Tabbed View 2.7.2. Schematic Symbols 2.7.3. Select Items in the Schematic View 2.7.4. Shortcut Menu Commands in the Schematic View 2.7.5. Filtering in the Schematic View 2.7.6. View Contents of Nodes in the Schematic View 2.7.7. Moving Nodes in the Schematic View 2.7.8. View LUT Representations in the Technology Map Viewer 2.7.9. Zoom Controls 2.7.10. Navigating with the Bird's Eye View 2.7.11. Partition the Schematic into Pages 2.7.12. Follow Nets Across Schematic Pages
2.8. State Machine Viewer x
2.8.1. State Diagram View 2.8.2. State Transition Table 2.8.3. State Encoding Table 2.8.4. Switch Between State Machines
2.8.3. State Encoding Table x
2.8.3.1. Select Items in the State Machine Viewer
3. Timing Closure and Optimization x
3.1. Optimize Multi Corner Timing 3.2. Critical Paths 3.3. Design Evaluation for Timing Closure 3.4. Design Analysis 3.5. Timing Optimization 3.6. Periphery to Core Register Placement and Routing Optimization 3.77.7. Scripting Support3.77.7. Scripting Support 3.8. Timing Closure and Optimization Revision History
3.2. Critical Paths x
3.2.1. Viewing Critical Paths
3.3. Design Evaluation for Timing Closure x
3.3.1. Review Compilation Results 3.3.2. Review Details of Timing Paths 3.3.3. Adjusting and Recompiling
3.3.1. Review Compilation Results x
3.3.1.1. Review Messages 3.3.1.2. Evaluate Physical Synthesis Results 3.3.1.3. Evaluate Fitter Netlist Optimizations 3.3.1.4. Evaluate Optimization Results 3.3.1.5. Evaluate Resource Usage 3.3.1.6. Evaluate Other Reports and Adjust Settings Accordingly 3.3.1.7. Evaluate Clustering Difficulty
3.3.1.5. Evaluate Resource Usage x
3.3.1.5.1. Global and Non-Global Usage 3.3.1.5.2. Routing Usage 3.3.1.5.3. Wires Added for Hold
3.3.2. Review Details of Timing Paths x
3.3.2.1. Show Timing Path Routing 3.3.2.2. Global Network Buffers 3.3.2.3. Resets and Global Networks 3.3.2.4. Suspicious Setup 3.3.2.5. Logic Depth 3.3.2.6. Auto Shift Register Replacement 3.3.2.7. Clocking Architecture 3.3.2.8. Timing Closure Recommendations
3.3.2.2. Global Network Buffers x
3.3.2.2.1. Source Location 3.3.2.2.2. Insertion Delay 3.3.2.2.3. Fan-Out 3.3.2.2.4. Global Networks
3.3.3. Adjusting and Recompiling x
3.3.3.1. Using Partitions to Achieve Timing Closure
3.4. Design Analysis x
3.4.1. Ignored Timing Constraints 3.4.2. I/O Timing 3.4.3. Register-to-Register Timing Analysis
3.4.3. Register-to-Register Timing Analysis x
3.4.3.1. Displaying Path Reports with the Timing Analyzer 3.4.3.2. Tips for Analyzing Failing Paths 3.4.3.3. Tips for Analyzing Failing Clock Paths that Cross Clock Domains 3.4.3.4. Tips for Analyzing Paths from/to the Source and Destination of Critical Path 3.4.3.5. Tips for Creating a .tcl Script to Monitor Critical Paths Across Compiles 3.4.3.6. Global Routing Resources
3.5. Timing Optimization x
3.5.1. Displaying Timing Closure Recommendations for Failing Paths 3.5.2. Timing Optimization Advisor 3.5.3. Optional Fitter Settings 3.5.4. I/O Timing Optimization Techniques 3.5.5. Register-to-Register Timing Optimization Techniques 3.5.6. Logic Lock (Standard) Assignments 3.5.7. Location Assignments 3.5.8. Metastability Analysis and Optimization Techniques
3.5.3. Optional Fitter Settings x
3.5.3.1. Optimize Hold Timing 3.5.3.2. Fitter Aggressive Routability Optimization
3.5.4. I/O Timing Optimization Techniques x
3.5.4.1. Optimize IOC Register Placement for Timing Logic Option 3.5.4.2. Fast Input, Output, and Output Enable Registers 3.5.4.3. Programmable Delays 3.5.4.4. Use PLLs to Shift Clock Edges 3.5.4.5. Use Fast Regional Clock Networks and Regional Clocks Networks 3.5.4.6. Spine Clock Limitations 3.5.4.7. Change How Hold Times are Optimized for Devices
3.5.5. Register-to-Register Timing Optimization Techniques x
3.5.5.1. Optimize Source Code 3.5.5.2. Improving Register-to-Register Timing 3.5.5.3. Physical Synthesis Optimizations 3.5.5.4. Turn Off Extra-Effort Power Optimization Settings 3.5.5.5. Optimize Synthesis for Speed, Not Area 3.5.5.6. Flatten the Hierarchy During Synthesis 3.5.5.7. Set the Synthesis Effort to High 3.5.5.8. Change State Machine Encoding 3.5.5.9. Duplicate Logic for Fan-Out Control 3.5.5.10. Prevent Shift Register Inference 3.5.5.11. Use Other Synthesis Options Available in Your Synthesis Tool 3.5.5.12. Fitter Seed 3.5.5.13. Set Maximum Router Timing Optimization Level
3.5.6. Logic Lock (Standard) Assignments x
3.5.6.1. Hierarchy Assignments
3.6. Periphery to Core Register Placement and Routing Optimization x
3.6.1. Setting Periphery to Core Optimizations in the Advanced Fitter Setting Dialog Box 3.6.2. Setting Periphery to Core Optimizations in the Assignment Editor 3.6.3. Viewing Periphery to Core Optimizations in the Fitter Report
3.77.7. Scripting Support3.77.7. Scripting Support x
3.7.1. Initial Compilation Settings 3.7.2. I/O Timing Optimization Techniques 3.7.3. Register-to-Register Timing Optimization Techniques
4. Area Optimization x
4.1. Resource Utilization Information 4.2. Optimizing Resource Utilization 4.3. Scripting Support 4.4. Area Optimization Revision History
4.1. Resource Utilization Information x
4.1.1. Flow Summary Report 4.1.2. Fitter Reports 4.1.3. Analysis and Synthesis Reports 4.1.4. Compilation Messages
4.2. Optimizing Resource Utilization x
4.2.1. Using the Resource Optimization Advisor 4.2.2. Resource Utilization Issues Overview 4.2.3. I/O Pin Utilization or Placement 4.2.4. Logic Utilization or Placement 4.2.5. Routing
4.2.3. I/O Pin Utilization or Placement x
4.2.3.1. Guideline: Use I/O Assignment Analysis 4.2.3.2. Guideline: Modify Pin Assignments or Choose a Larger Package
4.2.4. Logic Utilization or Placement x
4.2.4.1. Guideline: Optimize Source Code 4.2.4.2. Guideline: Optimize Synthesis for Area, Not Speed 4.2.4.3. Guideline: Restructure Multiplexers 4.2.4.4. Guideline: Perform WYSIWYG Primitive Resynthesis with Balanced or Area Setting 4.2.4.5. Guideline: Use Register Packing 4.2.4.6. Guideline: Remove Fitter Constraints 4.2.4.7. Guideline: Flatten the Hierarchy During Synthesis 4.2.4.8. Guideline: Re-target Memory Blocks 4.2.4.9. Guideline: Use Physical Synthesis Options to Reduce Area 4.2.4.10. Guideline: Retarget or Balance DSP Blocks 4.2.4.11. Guideline: Use a Larger Device
4.2.5. Routing x
4.2.5.1. Guideline: Set Auto Packed Registers to Sparse or Sparse Auto 4.2.5.2. Guideline: Set Fitter Aggressive Routability Optimizations to Always 4.2.5.3. Guideline: Increase Router Effort Multiplier 4.2.5.4. Guideline: Remove Fitter Constraints 4.2.5.5. Guideline: Optimize Synthesis for Area, Not Speed 4.2.5.6. Guideline: Optimize Source Code 4.2.5.7. Guideline: Use a Larger Device
4.3. Scripting Support x
4.3.1. Initial Compilation Settings 4.3.2. Resource Utilization Optimization Techniques
5. Analyzing and Optimizing the Design Floorplan x
5.1. Design Floorplan Analysis in the Chip Planner 5.2. Logic Lock (Standard) Regions 5.3. Using Logic Lock (Standard) Regions in the Chip Planner 5.4. Scripting Support 5.5. Analyzing and Optimizing the Design Floorplan Revision History
5.1. Design Floorplan Analysis in the Chip Planner x
5.1.1. Starting the Chip Planner 5.1.2. Chip Planner GUI Components 5.1.3. Viewing Architecture-Specific Design Information 5.1.4. Viewing Available Clock Networks in the Device 5.1.5. Viewing Routing Congestion 5.1.6. Viewing I/O Banks 5.1.7. Viewing High-Speed Serial Interfaces (HSSI) 5.1.8. Viewing the Source and Destination of Placed Nodes 5.1.9. Viewing Fan-In and Fan-Out Connections of Placed Resources 5.1.10. Generating Immediate Fan-In and Fan-Out Connections 5.1.11. Exploring Paths in the Chip Planner 5.1.12. Viewing Assignments in the Chip Planner 5.1.13. Viewing High-Speed and Low-Power Tiles in the Chip Planner 5.1.14. Viewing Design Partition Placement
5.1.2. Chip Planner GUI Components x
5.1.2.1. Chip Planner Toolbar 5.1.2.2. Layers Settings and Editing Modes 5.1.2.3. Locate History Window 5.1.2.4. Chip Planner Floorplan Views
5.1.11. Exploring Paths in the Chip Planner x
5.1.11.1. Analyzing Connections for a Path 5.1.11.2. Locate Path from the Timing Analysis Report to the Chip Planner 5.1.11.3. Show Delays 5.1.11.4. Viewing Routing Resources
5.2. Logic Lock (Standard) Regions x
5.2.1. Attributes of a Logic Lock (Standard) Region 5.2.2. Creating Logic Lock (Standard) Regions 5.2.3. Customizing the Shape of Logic Lock Regions 5.2.4. Placing Logic Lock (Standard) Regions 5.2.5. Placing Device Resources into Logic Lock (Standard) Regions 5.2.6. Hierarchical (Parent and Child) Logic Lock (Standard) Regions 5.2.7. Additional Intel® Quartus® Prime Logic Lock (Standard) Design Features 5.2.8. Logic Lock (Standard) Regions Window
5.2.2. Creating Logic Lock (Standard) Regions x
5.2.2.1. Creating Logic Lock (Standard) Regions with the Chip Planner 5.2.2.2. Creating Logic Lock (Standard) Regions with the Project Navigator 5.2.2.3. Creating Logic Lock (Standard) Regions with the Logic Lock (Standard) Regions Window 5.2.2.4. Defining Routing Regions 5.2.2.5. Noncontiguous Logic Lock (Standard) Regions 5.2.2.6. Considerations on Using Auto Sized Regions
5.2.3. Customizing the Shape of Logic Lock Regions x
5.2.3.1. Merging Logic Lock (Standard) Regions 5.2.3.2. Noncontiguous Logic Lock (Standard) Regions
5.2.5. Placing Device Resources into Logic Lock (Standard) Regions x
5.2.5.1. Empty Logic Lock Regions 5.2.5.2. Pin Assignment 5.2.5.3. Reserved Logic Lock (Standard) Regions 5.2.5.4. Excluded Resources 5.2.5.5. Logic Lock (Standard) Assignment Precedence 5.2.5.6. Virtual Pins
5.2.7. Additional Intel® Quartus® Prime Logic Lock (Standard) Design Features x
5.2.7.1. Analysis and Synthesis Resource Utilization by Entity 5.2.7.2. Intel® Quartus® Prime Revisions Feature
5.3. Using Logic Lock (Standard) Regions in the Chip Planner x
5.3.1. Viewing Connections Between Logic Lock (Standard) Regions in the Chip Planner 5.3.2. Using Logic Lock (Standard) Regions with the Design Partition Planner
5.4. Scripting Support x
5.4.1. Initializing and Uninitializing a Logic Lock (Standard) Region 5.4.2. Creating or Modifying Logic Lock (Standard) Regions 5.4.3. Obtaining Logic Lock (Standard) Region Properties 5.4.4. Assigning Logic Lock (Standard) Region Content 5.4.5. Save a Node-Level Netlist for the Entire Design into a Persistent Source File 5.4.6. Setting Logic Lock (Standard) Assignment Priority 5.4.7. Assigning Virtual Pins with a Tcl command
6. Netlist Optimizations and Physical Synthesis x
6.1. Physical Synthesis Optimizations 6.2. Applying Netlist Optimizations 6.3. Viewing Synthesis and Netlist Optimization Reports 6.4. Scripting Support 6.5. Netlist Optimizations and Physical Synthesis Revision History
6.1. Physical Synthesis Optimizations x
6.1.1. Enabling Physical Synthesis Optimization 6.1.2. Physical Synthesis Options 6.1.3. Perform Register Retiming for Performance 6.1.4. Preventing Register Movement During Retiming
6.2. Applying Netlist Optimizations x
6.2.1. WYSIWYG Primitive Resynthesis 6.2.2. Saving a Node-Level Netlist
6.4. Scripting Support x
6.4.1. Synthesis Netlist Optimizations 6.4.2. Physical Synthesis Optimizations 6.4.3. Back-Annotating Assignments
7. Engineering Change Orders with the Chip Planner x
7.1. Engineering Change Orders 7.2. ECO Design Flow 7.3. The Chip Planner Overview 7.4. Performing ECOs with the Chip Planner (Floorplan View) 7.5. Performing ECOs in the Resource Property Editor 7.6. Change Manager 3.77.7. Scripting Support3.77.7. Scripting Support 7.8. Common ECO Applications 7.9. Post ECO Steps 7.10. Engineering Change Orders with the Chip Planner Revision History
7.1. Engineering Change Orders x
7.1.1. Performance Preservation 7.1.2. Compilation Time 7.1.3. Verification 7.1.4. Change Modification Record
7.3. The Chip Planner Overview x
7.3.1. Opening the Chip Planner 7.3.2. The Chip Planner Tasks and Layers
7.4. Performing ECOs with the Chip Planner (Floorplan View) x
7.4.1. Creating, Deleting, and Moving Atoms 7.4.2. Check and Save Netlist Changes
7.5. Performing ECOs in the Resource Property Editor x
7.5.1. Logic Elements 7.5.2. Adaptive Logic Modules 7.5.3. FPGA I/O Elements 7.5.4. FPGA RAM Blocks 7.5.5. FPGA DSP Blocks
7.5.1. Logic Elements x
7.5.1.1. Logic Element Properties 7.5.1.2. Modes of Operation 7.5.1.3. Sum and Carry Equations 7.5.1.4. sload and sclr Signals 7.5.1.5. Register Cascade Mode 7.5.1.6. Cell Delay Table 7.5.1.7. Logic Element Connections 7.5.1.8. Deleting a Logic Element
7.5.2. Adaptive Logic Modules x
7.5.2.1. Adaptive Logic Module Schematic 7.5.2.2. Adaptive Logic Module Properties 7.5.2.3. Adaptive Logic Module Connections
7.5.3. FPGA I/O Elements x
7.5.3.1. Stratix V I/O Elements 7.5.3.2. Stratix IV I/O Elements 7.5.3.3. Arria V I/O Elements 7.5.3.4. Cyclone V I/O Elements 7.5.3.5. MAX V I/O Elements
7.6. Change Manager x
7.6.1. Complex Changes in the Change Manager 7.6.2. Managing Signal Probe Signals 7.6.3. Exporting Changes
7.8. Common ECO Applications x
7.8.1. Adjust the Drive Strength of an I/O with the Chip Planner 7.8.2. Modify the PLL Properties With the Chip Planner 7.8.3. PLL Properties 7.8.4. Modify the Connectivity between Resource Atoms
7.8.3. PLL Properties x
7.8.3.1. Adjusting the Duty Cycle 7.8.3.2. Adjusting the Phase Shift 7.8.3.3. Adjusting the Output Clock Frequency 7.8.3.4. Adjusting the Spread Spectrum
1. Design Optimization Overview
2. Optimizing the Design Netlist
3. Timing Closure and Optimization
4. Area Optimization
5. Analyzing and Optimizing the Design Floorplan
6. Netlist Optimizations and Physical Synthesis
7. Engineering Change Orders with the Chip Planner
A. Intel® Quartus® Prime Standard Edition User Guides

1.3.3. Reducing Critical Path Delay

To meet complex timing requirements involving multiple clocks, routing resources, and area constraints, the Intel® Quartus® Prime software offers a close interaction between synthesis, floorplan editing, place-and-route, and timing analysis processes.

By default, the Intel® Quartus® Prime Fitter works to meet the timing requirements, and stops when the requirements are met. Therefore, realistic constraints are crucial for timing closure.

Under-constrained designs can lead to sub-optimal results. For over-constrained designs, the Fitter might over-optimize non-critical paths at the expense of true critical paths. In addition, area and compilation time may also increase.

For designs with high resource usage, the Intel® Quartus® Prime Fitter might have trouble finding a legal placement. In such circumstances, the Fitter automatically modifies settings to try to trade off performance for area.

The Intel® Quartus® Prime Fitter offers advanced options that can help improve the design performance when you properly set constraints. Use the Timing Optimization Advisor to determine which options are best suited for the design.

If you use incremental compilation, you can help resolve inter-partition timing requirements by locking down results, one partition at a time, or by guiding the placement of the partitions with Logic Lock (Standard) regions. You might improve the timing on such paths by placing the partitions optimally to reduce the length of critical paths. Once the inter-partition timing requirements are met, use incremental compilation to preserve the results and work on partitions that have not met timing requirements.

In high-density FPGAs, routing accounts for a major part of critical path timing. Because of this, duplicating or retiming logic can allow the Fitter to reduce delay on critical paths. The Intel® Quartus® Prime software offers push-button netlist optimizations and physical synthesis options that can improve design performance at the expense of considerable increases of compilation time and area. Turn on only those options that help you keep reasonable compilation times and resource usage. Alternately, you can modify the HDL to manually duplicate or adjust the timing logic.

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