Tasks provide a framework for running the VTR flow on multiple benchmarks, architectures and with multiple CAD tool parameters.

A task specifies a set of benchmark circuits, architectures and CAD tool parameters to be used. By default, tasks execute the run_vtr_flow script for every circuit/architecture/CAD parameter combination.

Example Tasks

  • basic_flow: Runs the VTR flow mapping a simple Verilog circuit to an FPGA architecture.

  • timing: Runs the flagship VTR benchmarks on a comprehensive, realistic architecture file.

  • timing_chain: Same as timing but with carry chains.

  • regression_mcnc: Runs VTR on the historical MCNC benchmarks on a legacy architecture file. (Note: This is only useful for comparing to the past, it is not realistic in the modern world)

  • regression_titan/titan_small: Runs a small subset of the Titan benchmarks targetting a simplified Altera Stratix IV (commercial FPGA) architecture capture

  • regression_fpu_hard_block_arch: Custom hard FPU logic block architecture

Directory Layout

All of VTR’s included tasks are located here:


If users wishes to create their own task, they must do so in this location.

All tasks must contain a configuration file located here:


Fig. 13 illustrates the directory layout for a VTR task. Every time the task is run a new run<#> directory is created to store the output files, where <#> is the smallest integer to make the run directory name unique.

The symbolic link latest will point to the most recent run<#> directory.


Fig. 13 Task directory layout.

Creating a New Task

  1. Create the folder $VTR_ROOT/vtr_flow/tasks/<task_name>

  2. Create the folder $VTR_ROOT/vtr_flow/tasks/<task_name>/config

  3. Create and configure the file $VTR_ROOT/vtr_flow/tasks/<task_name>/config/config.txt

Task Configuration File

The task configuration file contains key/value pairs separated by the = character. Comment line are indicted using the # symbol.

Example configuration file:

# Path to directory of circuits to use

# Path to directory of architectures to use

# Add circuits to list to sweep

# Add architectures to list to sweep

# Parse info and how to parse


run_vtr_task will invoke the script (default run_vtr_flow) for the cartesian product of circuits, architectures and script parameters specified in the config file.

Required Fields

  • circuit_dir: Directory path of the benchmark circuits.

    Absolute path or relative to $VTR_ROOT/vtr_flow/.

  • arch_dir: Directory path of the architecture XML files.

    Absolute path or relative to $VTR_ROOT/vtr_flow/.

  • circuit_list_add: Name of a benchmark circuit file.

    Use multiple lines to add multiple circuits.

  • arch_list_add: Name of an architecture XML file.

    Use multiple lines to add multiple architectures.

  • parse_file: Parse Configuration file used for parsing and extracting the statistics.

    Absolute path or relative to $VTR_ROOT/vtr_flow/parse/parse_config.

Optional Fields

  • script_path: Script to run for each architecture/circuit combination.

    Absolute path or relative to $VTR_ROOT/vtr_flow/scripts/ or $VTR_ROOT/vtr_flow/tasks/<task_name>/config/)

    Default: run_vtr_flow

    Users can set this option to use their own script instead of the default. The circuit path will be provided as the first argument, and architecture path as the second argument to the user script.

  • script_params_common: Common parameters to be passed to all script invocations.

    This can be used, for example, to run partial VTR flows.

    Default: none

  • script_params: Alias for script_params_common

  • script_params_list_add: Adds a set of command-line arguments

    Multiple script_params_list_add can be provided which are addded to the cartesian product of configurations to be evaluated.

  • sdc_dir: Directory path to benchmark SDC files.

    Absolute path or relative to $VTR_ROOT/vtr_flow/.

    If provided, each benchmark will look for a similarly named SDC file.

    For instance with circuit_list_add=my_circuit.v or circuit_list_add=my_circuit.blif, the flow would look for an SDC file named my_circuit.sdc within the specified sdc_dir.

  • includes_dir: Directory path to benchmark _include_ files

    Absolute path or relative to $VTR_ROOT/vtr_flow/.

    Note: Multiple includes_dir are NOT allowed in a task config file.

  • include_list_add: A path to an include file, which is relative to includes_dir

    Multiple include_list_add can be provided.

    include files could act as the top module complementary, like definitions, memory initialization files, macros or sub-modules.

    Note: Only include files, written in supported HDLs by each frontend, are synthesized. The others are only copied to the destination folder.

    Note: include files will be shared among all benchmark circuits in the task config file.

  • pass_requirements_file: Pass Requirements file.

    Absolute path or relative to $VTR_ROOT/vtr_flow/parse/pass_requirements/ or $VTR_ROOT/vtr_flow/tasks/<task_name>/config/

    Default: none