# Building and Installing » Benchmark Taskflow

## Compile and Run Benchmarks

To build the benchmark code, enable the CMake option `TF_BUILD_BENCHMARKS` to `ON` as follows:

    # under /taskflow/build
    ~$ cmake ../ -DTF_BUILD_BENCHMARKS=ON
    ~$ make

After you successfully build the benchmark code, you can find all benchmark instances in the `benchmarks/` folder. You can run the executable of each instance in the corresponding folder.

    ~$ cd benchmarks & ls
    black_scholes binary_tree graph_traversal ...
    ~$ cd graph_traversal & ./graph_traversal
    |V|+|E|     Runtime
          2       0.197
        842       0.198
       3284       0.488
       7288       0.774
        ...         ...
        ...         ...
     619802      75.135
     664771      77.436
     711200      83.957

You can display the help message by giving the option `--help`.

    ~$ ./graph_traversal --help
    Graph Traversal
    Usage: ./graph_traversal [OPTIONS]

    Options:
      -h,--help                   Print this help message and exit
      -t,--num_threads UINT       number of threads (default=1)
      -r,--num_rounds UINT        number of rounds (default=1)
      -m,--model TEXT             model name tbb|omp|tf (default=tf)

We currently implement the following instances that are commonly used by the parallel computing community to evaluate the system performance.

Instance | Description
--- | ---
binary_tree | traverses a complete binary tree
black_scholes | computes option pricing with Black-Shcoles Models
graph_traversal | traverses a randomly generated direct acyclic graph
linear_chain | traverses a linear chain of tasks
mandelbrot | exploits imbalanced workloads in a Mandelbrot set
matrix_multiplication | multiplies two 2D matrices
mnist | trains a neural network-based image classifier on the MNIST dataset
parallel_sort | sorts a range of items
reduce_sum | sums a range of items using reduction
wavefront | propagates computations in a 2D grid
linear_pipeline | pipeline scheduling on a linear chain of pipes
graph_pipeline | pipeline scheduling on a graph of pipes

## Configure Run Options

We implement consistent options for each benchmark instance. Common options are:

option | value | function
--- | --- | ---
`-h` | none | display the help message
`-t` | integer | configure the number of threads to run
`-r` | integer | configure the number of rounds to run
`-m` | string | configure the baseline models to run, tbb, omp, or tf

You can configure the benchmarking environment by giving different options.

### Specify the Run Model

In addition to a Taskflow-based implementation for each benchmark instance, we have implemented two baseline models using the state-of-the-art parallel programming libraries, OpenMP and Intel TBB, to measure and evaluate the performance of Taskflow. You can select different implementations by passing the option `-m`.

    ~$ ./graph_traversal -m tf   # run the Taskflow implementation (default)
    ~$ ./graph_traversal -m tbb  # run the TBB implementation
    ~$ ./graph_traversal -m omp  # run the OpenMP implementation

### Specify the Number of Threads

You can configure the number of threads to run a benchmark instance by passing the option `-t`. The default value is one.

    # run the Taskflow implementation using 4 threads
    ~$ ./graph_traversal -m tf -t 4

Depending on your environment, you may need to use `taskset` to set the CPU affinity of the running process. This allows the OS scheduler to keep process on the same CPU(s) as long as practical for performance reason.

    # affine the process to 4 CPUs, CPU 0, CPU 1, CPU 2, and CPU 3
    ~$ taskset -c 0-3 graph_traversal -t 4

### Specify the Number of Rounds

Each benchmark instance evaluates the runtime of the implementation at different problem sizes. Each problem size corresponds to one iteration. You can configure the number of rounds per iteration to average the runtime.

    # measure the runtime in an average of 10 runs
    ~$ ./graph_traversal -r 10
    |V|+|E|     Runtime
          2       0.109   # the runtime value 0.109 is an average of 10 runs
        842       0.298
        ...         ...
     619802      73.135
     664771      74.436

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