AN 456: PCI Express High Performance Reference Design

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ID 683541
Date 12/12/2018
Public
Document Table of Contents
Document Table of Contents x
1. PCI Express High Performance Reference Design
1. PCI Express High Performance Reference Design x
1.1. Understanding Throughput in PCI Express 1.2. Deliverables Included with the Reference Design 1.3. Reference Design Functional Description 1.4. Hardware Requirements 1.5. Software Requirements 1.6. Software Installation 1.7. Hardware Installation 1.8. Running the Software Application 1.9. Additional Chaining DMA Commands 1.10. Using SignalTap II 1.11. Performance Benchmarking Results 1.12. Document Revision History
1.1. Understanding Throughput in PCI Express x
1.1.1. Protocol Overhead 1.1.2. Throughput for Posted Writes 1.1.3. Throughput for Reads
1.3. Reference Design Functional Description x
1.3.1. File Naming Conventions 1.3.2. Project Hierarchy Arria V, Cyclone V, and Stratix V Directory Structure Arria II GX, Cyclone IV GX, and Stratix IV GX Directory Structure IP Core Settings Quartus II Settings
1.7. Hardware Installation x
1.7.1. Programming using the .sof File
1. PCI Express High Performance Reference Design

1.3.2. Project Hierarchy

The directory structure used for the Arria V, Cyclone V, and Stratix V reference design differs from the earlier device families.

Arria V, Cyclone V, and Stratix V Directory Structure

Arria V, Cyclone V, and Stratix V devices use the following directory structure:

  • top—the project directory. The top-level entity is top_example_chaining_top.
  • pcie_lib—includes all design files. If you modify the design, you must copy the modified files to the pcie_lib directory before recompiling the design.

Arria II GX, Cyclone IV GX, and Stratix IV GX Directory Structure

These devices use the following directory structure:

  • top or top_ <n> gx—top is the top-level project directory for the hard IP implementation. The soft IP implementation may have a <n> gx suffix where <n> indicates the number of lanes. In both cases, the top-level entity is top_example_chaining_top.
  • top_examples/chaining_dma—includes design files to implement the chaining DMA.
  • ip_compiler_for_pci_express—includes library files for PCI Express.

IP Core Settings

The reference design supports a maximum payload size of 512 Bytes. The desired performance for received completions and requests is set to Maximum. The following tables show the settings for supported devices.

Table 2.  System Settings for PCI Express IP Core–Stratix V GX Device
Parameter Value
PCIe IP core type PCI Express hard IP
PCIe System Parameters
PHY type Stratix V GX
PHY interface Serial
System Settings
Number of lanes x8
Lane rate Gen2 (5.0 Gbps)
Port type Native endpoint
PCI Express Base Specification version 2.1
Application interface Avalon-ST 128-bit
RX buffer credit allocation Low
Reference clock frequency 100 MHz
Use 62.5 MHz application clock OFF
Use deprecated RX Avalon-ST data byte enable port(rx_st_be) ON
Enable byte parity ports on Avalon-ST interface OFF
Enable multiple packets per cycle OFF
Enable configuration via the PCIe link OFF
Use credit consumed selection port tx_cons_cred_sel OFF
Enable Configuration Bypass OFF
Enable Hard IP reconfiguration OFF
Table 3.  PCI Register Settings–Stratix V GX Device
PCI Base Address Registers (Type 0 Configuration Space)
BAR BAR Type BAR Size
0 32-bit Non-Prefetchable Memory 256 MBytes - 28 bits
1 Disabled N/A
2 32-bit Non-Prefetchable Memory 1 KBytes - 10 bits
Base and Limit Registers for Root Ports
Input/Output Disabled
Prefetchable memory Disabled
PCI Read-Only Registers
Register Name Value Additional Information
Vendor ID 0x1172 The Vendor ID can be either 0x1172 or 0xB0D8. This parameter has no effect on design behavior.
Device ID 0xE001 N/A
Revision ID 0x1 N/A
Class Code 0x00FF0000 N/A
Subsystem Vendor ID 0xA8 For this design, theSubsystem Vendor ID is the encoded value used by the GUI to identify the device family and configuration. Consequently, it changes depending on the settings specified.
Subsystem Device ID 0x2801 N/A
Table 4.  Capabilities Parameters–Stratix V GX Device
Capability Registers
Device Capabilities
Maximum payload size 256 Bytes
Number of tags supported 32
Completion timeout range ABCD
Implement completion timeout disable ON
Error Reporting
Advanced error reporting (AER) Off
ECRC check Off
ECRC generation Off
ECRC forwarding Off
Track receive completion buffer overflow Off
Link Capabilities
Link port number 1
Data link layer active reporting Off
Surprise down reporting Off
Slot clock configuration On
MSI Capabilities
MSI messages requested 4
MSI-X Capabilities
Implement MSI-X Off
MSI-X Table size 0
MSI-X Table Offset 0x0
MSI-X Table BAR Indicator (BIR) 1
Pending Bit Array (PBA) 0x0
Offset 0
BAR Indicator 0
Slot Capabilities
Use slot register Off
Slot power scale 0
Slot power limit 0
Slot number 0
Table 5.  Power Management Parameters–Stratix V GX Device
Parameter Value
Power Management
Endpoint L0s acceptable latency Maximum of 64 ns
Endpoint L1 acceptable latency Maximum of 1 us
PHY Characteristics
Gen2 transmit deemphasis 6dB

Quartus II Settings

The .qar files in the reference design package has the recommended synthesis, Fitter, and timing analysis settings. These settings are optimized for the parameters chosen in this reference design.

Level Two Title