ARCHITECTURE.md

Architecture Customization Guide

Table of Contents

• Multi-Die FPGA Architecture
• Architecture Definition Format
  • Overview
  • Example Architecture
• Customizing the Architecture
  • Steps to Customize
• SLL Counts Lookup Table
  • Generating Custom Tables
  • Integration Steps
• Best Practices

Multi-Die FPGA Architecture

OpenPARF supports customization of multi-die FPGA architectures through a structured XML format. This guide explains how to define and modify architectures for your specific needs.

Architecture Definition Format

Overview

Architecture files are located at benchmarks/arch/ultrascale/multi-die_layout_<{num_cols}x{num_rows}>.xml. The XML format includes several key sections:

• <resources>: Define available FPGA resources
• <primitives>: Specify primitive elements
• <global_sw>: Global switch configurations
• <tile_blocks>: Define tile block structures
• <cores>: Core specifications
• <chip>: Overall chip topology and SLR configuration

Example Architecture

Here's a sample 2x2 SLR topology:

<chip name="demo_chip">
    <grid name="chip_grid" cols="2" rows="2">
        <core name="CORE_0" type="CORE_A" x="0" y="0" width="168" height="120"/>
        <core name="CORE_1" type="CORE_A" x="0" y="1" width="168" height="120"/>
        <core name="CORE_2" type="CORE_B" x="1" y="0" width="168" height="120"/>
        <core name="CORE_3" type="CORE_B" x="1" y="1" width="168" height="120"/>
    </grid>
</chip>

Customizing the Architecture

Steps to Customize

1. Define SLR Topology

   • Modify the <grid> attributes in <chip> section
   • Set appropriate cols and rows values

2. Configure Cores

   • Define each core with unique name
   • Specify type, position (x,y), and dimensions (width,height)
   • Ensure core specifications match SLR requirements

3. Adjust Resources

   • Customize <resources>, <primitives>, and other sections as needed
   • Maintain consistency with core configurations

4. Verify Configuration

   • Check all specifications for correctness
   • Ensure topology matches design requirements

SLL Counts Lookup Table

Generating Custom Tables

For SLR topologies beyond 1x4 or 2x2, generate a custom SLL counts lookup table:

python compute_sll_counts_table.py --num_cols <num cols> --num_rows <num rows> --output <filename>

Integration Steps

1. Generate Table

   • Run script with desired dimensions
   • Table will be saved as <filename>.npy

2. Install Table

   • Move generated .npy file to <installation directory>/openparf/ops/sll/
   • Update code in sll.py to use new table:

else:
    self.sll_counts_table = torch.from_numpy(
        np.load(
            os.path.join(
                os.path.dirname(os.path.abspath(__file__)),
                "<filename>.npy"))).to(dtype=torch.int32)

Best Practices

1. Keep dimensions reasonable (typically ≤ 5x5 due to fabrication limits)
2. Maintain consistent resource distribution
3. Verify all specifications before implementation
4. Document custom configurations
5. Test thoroughly after modifications