conbench 1.41.0

Continuous Benchmarking (CB) Framework

Conbench

Conbench allows you to write benchmarks in any language, publish the results as JSON via an API, and persist them for comparison while iterating on performance improvements or to guard against regressions.

Conbench includes a runner which can be used as a stand-alone library for traditional benchmark authoring. The runner will time a unit of work (or measure throughput), collect machine information that may be relevant for hardware specific optimizations, and return JSON formatted results.

You can optionally host a Conbench server (API & dashboard) to share benchmark results more widely, explore the changes over time, and compare results across varying benchmark machines, languages, and cases.

There is also a Conbench command line interface, useful for Continuous Benchmarking (CB) orchestration alongside your development pipeline.

The Apache Arrow project is using Conbench for Continuous Benchmarking. They have both native Python Conbench benchmarks, and Conbench benchmarks written in Python that know how to execute their external C++/R/Java/JavaScript benchmarks and record those results too. Those benchmarks can be found in the ursacomputing/benchmarks repository, and the results are hosted on the Arrow Conbench Server.

• May 2021: https://ursalabs.org/blog/announcing-conbench/

Index

• Contributing
• Authoring benchmarks
  • Simple benchmarks
  • External benchmarks
  • Case benchmarks
  • R benchmarks

Contributing

Create workspace

$ cd
$ mkdir -p envs
$ mkdir -p workspace

Create virualenv

$ cd ~/envs
$ python3 -m venv conbench
$ source conbench/bin/activate

Clone repository

(conbench) $ cd ~/workspace/
(conbench) $ git clone https://github.com/conbench/conbench.git

Install dependencies

(conbench) $ cd ~/workspace/conbench/
(conbench) $ pip install -r requirements-test.txt
(conbench) $ pip install -r requirements-build.txt
(conbench) $ pip install -r requirements-cli.txt
(conbench) $ pip install -e .

Start postgres

Mac

$ brew services start postgres

Linux

$ sudo service postgresql start

Create databases

$ psql
# CREATE DATABASE conbench_test;
# CREATE DATABASE conbench_prod;

Launch app

(conbench) $ flask run
 * Serving Flask app "api.py" (lazy loading)
 * Environment: development
 * Debug mode: on
 * Running on http://127.0.0.1:5000/ (Press CTRL+C to quit)

If you get an authentication error, set the password for your user.

$ psql
# ALTER USER <username> PASSWORD '<password>';

Then, set an environmental variable DB_PASSWORD to reflect the chosen password.

$ export DB_PASSWORD=<password>

Alternatively, if you don't want to set the DB_PASSWORD you can change the password in postgres to postgres.

$ psql
# ALTER USER <username> PASSWORD 'postgres';

Test app

$ curl http://127.0.0.1:5000/api/ping/
{
  "date": "Fri, 23 Oct 2020 03:09:58 UTC"
}

View API docs

http://localhost:5000/api/docs/

Run tests

(conbench) $ cd ~/workspace/conbench/
(conbench) $ pytest -vv conbench/tests/

Format code

(conbench) $ cd ~/workspace/conbench/
(conbench) $ black .
    reformatted foo.py
(conbench) $ git add foo.py

Sort imports

(conbench) $ cd ~/workspace/conbench/
(conbench) $ isort .
    Fixing foo.py
(conbench) $ git add foo.py

Lint code

(qa) $ cd ~/workspace/conbench/
(qa) $ flake8
./foo/bar/__init__.py:1:1: F401 'FooBar' imported but unused

Generate coverage report

(conbench) $ cd ~/workspace/conbench/
(conbench) $ coverage run --source conbench -m pytest conbench/tests/
(conbench) $ coverage report -m

Test migrations with the database running using brew

(conbench) $ cd ~/workspace/conbench/
(conbench) $ brew services start postgres
(conbench) $ dropdb conbench_prod
(conbench) $ createdb conbench_prod
(conbench) $ alembic upgrade head

Test migrations with the database running as a docker container

(conbench) $ cd ~/workspace/conbench/
(conbench) $ brew services stop postgres
(conbench) $ docker-compose down
(conbench) $ docker-compose build
(conbench) $ docker-compose run migration

To autogenerate a migration

(conbench) $ cd ~/workspace/conbench/
(conbench) $ brew services start postgres
(conbench) $ dropdb conbench_prod
(conbench) $ createdb conbench_prod
(conbench) $ git checkout main && git pull    
(conbench) $ alembic upgrade head
(conbench) $ git checkout your-branch
(conbench) $ alembic revision --autogenerate -m "new"

To upload new version of conbench package to PyPI

1. Update version in setup.py
2. Commit your change into main branch

New version of conbench package will be uploaded into PyPI by a new build for conbench-deploy Buildkite pipeline

Authoring benchmarks

There are three main types of benchmarks: "simple benchmarks" that time the execution of a unit of work, "external benchmarks" that just record benchmark results that were obtained from some other benchmarking tool, and "case benchmarks" which benchmark a unit of work under different scenarios (cases).

Included in this repository are contrived, minimal examples of these different kinds of benchmarks to be used as templates for benchmark authoring. These example benchmarks and their tests can be found here:

• _example_benchmarks.py
• test_cli.py
• test_runner.py

Example simple benchmarks

A "simple benchmark" runs and records the execution time of a unit of work.

Implementation details: Note that this benchmark extends conbench.runner.Benchmark, implements the minimum required run() method, and registers itself with the @conbench.runner.register_benchmark decorator.

import conbench.runner


@conbench.runner.register_benchmark
class SimpleBenchmark(conbench.runner.Benchmark):
    """Example simple benchmark."""

    name = "addition"

    def run(self, **kwargs):
        yield self.conbench.benchmark(
            self._get_benchmark_function(), self.name, options=kwargs
        )

    def _get_benchmark_function(self):
        return lambda: 1 + 1

Successfully registered benchmarks appear in the conbench --help list.

(conbench) $ cd ~/workspace/conbench/conbench/tests/benchmark/
(conbench) $ conbench --help
Usage: conbench [OPTIONS] COMMAND [ARGS]...

  Conbench: Language-independent Continuous Benchmarking (CB) Framework

Options:
  --help  Show this message and exit.

Commands:
  addition            Run addition benchmark.
  external            Run external benchmark.
  external-r          Run external-r benchmark.
  external-r-options  Run external-r-options benchmark.
  list                List of benchmarks (for orchestration).
  matrix              Run matrix benchmark(s).
  version             Display Conbench version.

Benchmarks can be run from command line within the directory where the benchmarks are defined.

Benchmark classes can also be imported and executed via the run method which accepts the same arguments that appear in the command line help.

(conbench) $ cd ~/workspace/conbench/conbench/tests/benchmark/
(conbench) $ conbench addition --help

Usage: conbench addition [OPTIONS]

  Run addition benchmark.

Options:
  --iterations INTEGER   [default: 1]
  --drop-caches BOOLEAN  [default: false]
  --gc-collect BOOLEAN   [default: true]
  --gc-disable BOOLEAN   [default: true]
  --show-result BOOLEAN  [default: true]
  --show-output BOOLEAN  [default: false]
  --run-id TEXT          Group executions together with a run id.
  --run-name TEXT        Name of run (commit, pull request, etc).
  --help                 Show this message and exit.

Example command line execution:

(conbench) $ cd ~/workspace/conbench/conbench/tests/benchmark/
(conbench) $ conbench addition

Benchmark result:
{
    "run_id": "c7e5280e65d24ec19d64a7636cef1bd4",
    "batch_id": "c7e5280e65d24ec19d64a7636cef1bd4",
    "timestamp": "2021-06-21T22:18:16.752993+00:00",
    "context": {
        "benchmark_language": "Python",
        "benchmark_language_version": "Python 3.9.2"
    },
    "github": {
        "commit": "58fb35dc593dca82c917cf18c1c65c059b9fb12c",
        "repository": "https://github.com/conbench/conbench"
    },
    "machine_info": {
        "architecture_name": "x86_64",
        "cpu_core_count": "2",
        "cpu_frequency_max_hz": "3500000000",
        "cpu_l1d_cache_bytes": "32768",
        "cpu_l1i_cache_bytes": "32768",
        "cpu_l2_cache_bytes": "262144",
        "cpu_l3_cache_bytes": "4194304",
        "cpu_model_name": "Intel(R) Core(TM) i7-7567U CPU @ 3.50GHz",
        "cpu_thread_count": "4",
        "kernel_name": "20.5.0",
        "memory_bytes": "17179869184",
        "name": "machine-abc",
        "os_name": "macOS",
        "os_version": "10.16"
    },
    "stats": {
        "data": [
            "0.000003"
        ],
        "iqr": "0.000000",
        "iterations": 1,
        "max": "0.000003",
        "mean": "0.000003",
        "median": "0.000003",
        "min": "0.000003",
        "q1": "0.000003",
        "q3": "0.000003",
        "stdev": 0,
        "time_unit": "s",
        "times": [],
        "unit": "s"
    },
    "tags": {
        "name": "addition"
    }
}

Example Python execution:

(conbench) $ python
>>> import json
>>> from conbench.tests.benchmark import _example_benchmarks
>>> benchmark = _example_benchmarks.SimpleBenchmark()
>>> [(result, output)] = benchmark.run(iterations=10)
>>> output
2
>>> print(json.dumps(result, indent=2))
{
  "run_id": "9dc1beadf4bb46e0ac86cd0bb6fe201f",
  "batch_id": "9dc1beadf4bb46e0ac86cd0bb6fe201f",
  "timestamp": "2021-08-20T16:05:57.299148+00:00",
  "stats": {
    "data": [
      "0.000004",
      "0.000000",
      "0.000001",
      "0.000000",
      "0.000000",
      "0.000001",
      "0.000000",
      "0.000001",
      "0.000000",
      "0.000000"
    ],
    "times": [],
    "unit": "s",
    "time_unit": "s",
    "iterations": 10,
    "mean": "0.000001",
    "median": "0.000000",
    "min": "0.000000",
    "max": "0.000004",
    "stdev": "0.000001",
    "q1": "0.000000",
    "q3": "0.000001",
    "iqr": "0.000001"
  },
  "machine_info": {
    "name": "machine-xyz",
    "os_name": "macOS",
    "os_version": "10.16",
    "architecture_name": "x86_64",
    "kernel_name": "20.5.0",
    "memory_bytes": "17179869184",
    "cpu_model_name": "Apple M1",
    "cpu_core_count": "8",
    "cpu_thread_count": "8",
    "cpu_l1d_cache_bytes": "65536",
    "cpu_l1i_cache_bytes": "131072",
    "cpu_l2_cache_bytes": "4194304",
    "cpu_l3_cache_bytes": "0",
    "cpu_frequency_max_hz": "2400000000"
  },
  "context": {
    "benchmark_language": "Python",
    "benchmark_language_version": "Python 3.9.6"
  },
  "tags": {
    "name": "addition"
  },
  "github": {
    "commit": "58fb35dc593dca82c917cf18c1c65c059b9fb12c",
    "repository": "https://github.com/conbench/conbench"
  }
}

By default, Conbench will try to publish your results to a Conbench server. If you don't have one running or are missing a .conbench credentials file, you'll see error messages like the following when you execute benchmarks.

POST http://localhost:5000/api/login/ failed
{
  "code": 400,
  "description": {
    "_errors": [
      "Invalid email or password."
    ]
  },
  "name": "Bad Request"
}

POST http://localhost:5000/api/benchmarks/ failed
{
  "code": 401,
  "name": "Unauthorized"
}

To publish your results to a Conbench server, place a .conbench file in the same directory as your benchmarks. The cat command below shows the contents of an example .conbench config file.

(conbench) $ cd ~/workspace/conbench/conbench/tests/benchmark/
(conbench) $ cat .conbench
url: http://localhost:5000
email: [e-mail]
password: conbench

If you don't yet have a Conbench server user account, you'll need to create one to publish results (registration key defaults to conbench).

• http://localhost:5000/register/

Example external benchmarks

An "external benchmark" records results that were obtained from some other benchmarking tool (like executing an R benchmark from command line, parsing the resulting JSON, and recording those results).

Implementation details: Note that the following benchmark sets external = True, and calls self.conbench.record() rather than self.conbench.benchmark() as the example above does.

import conbench.runner


@conbench.runner.register_benchmark
class ExternalBenchmark(conbench.runner.Benchmark):
    """Example benchmark that just records external results."""

    external = True
    name = "external"

    def run(self, **kwargs):
        # external results from an API call, command line execution, etc
        result = {
            "data": [100, 200, 300],
            "unit": "i/s",
            "times": [0.100, 0.200, 0.300],
            "time_unit": "s",
        }

        context = {"benchmark_language": "C++"}
        yield self.conbench.record(
            result, self.name, context=context, options=kwargs, output=result
        )

(conbench) $ cd ~/workspace/conbench/conbench/tests/benchmark/
(conbench) $ conbench external --help

Usage: conbench external [OPTIONS]

  Run external benchmark.

Options:
  --show-result BOOLEAN  [default: true]
  --show-output BOOLEAN  [default: false]
  --run-id TEXT          Group executions together with a run id.
  --run-name TEXT        Name of run (commit, pull request, etc).
  --help                 Show this message and exit.

Note that the use of --iterations=3 results in 3 runs of the benchmark, and the mean, stdev, etc calculated.

(conbench) $ cd ~/workspace/conbench/conbench/tests/benchmark/
(conbench) $ conbench external --iterations=3

Benchmark result:
{
    "run_id": "8058dde1491b49e5bd514646797c2a20",
    "batch_id": "8058dde1491b49e5bd514646797c2a20",
    "timestamp": "2021-06-21T22:16:54.786499+00:00",
    "context": {
        "benchmark_language": "C++"
    },
    "github": {
        "commit": "58fb35dc593dca82c917cf18c1c65c059b9fb12c",
        "repository": "https://github.com/conbench/conbench"
    },
    "machine_info": {
        "architecture_name": "x86_64",
        "cpu_core_count": "2",
        "cpu_frequency_max_hz": "3500000000",
        "cpu_l1d_cache_bytes": "32768",
        "cpu_l1i_cache_bytes": "32768",
        "cpu_l2_cache_bytes": "262144",
        "cpu_l3_cache_bytes": "4194304",
        "cpu_model_name": "Intel(R) Core(TM) i7-7567U CPU @ 3.50GHz",
        "cpu_thread_count": "4",
        "kernel_name": "20.5.0",
        "memory_bytes": "17179869184",
        "name": "machine-abc",
        "os_name": "macOS",
        "os_version": "10.16"
    },
    "stats": {
        "data": [
            "100.000000",
            "200.000000",
            "300.000000"
        ],
        "iqr": "100.000000",
        "iterations": 3,
        "max": "300.000000",
        "mean": "200.000000",
        "median": "200.000000",
        "min": "100.000000",
        "q1": "150.000000",
        "q3": "250.000000",
        "stdev": "100.000000",
        "time_unit": "s",
        "times": [
            "0.100000",
            "0.200000",
            "0.300000"
        ],
        "unit": "i/s"
    },
    "tags": {
        "name": "external"
    }
}

Example case benchmarks

A "case benchmark" is a either a "simple benchmark" or an "external benchmark" executed under various predefined scenarios (cases).

Implementation details: Note that the following benchmark declares the valid combinations in valid_cases, which reads like a CSV (the first row contains the cases names).

import conbench.runner


@conbench.runner.register_benchmark
class CasesBenchmark(conbench.runner.Benchmark):
    """Example benchmark with cases."""

    name = "matrix"
    valid_cases = (
        ("rows", "columns"),
        ("10", "10"),
        ("2", "10"),
        ("10", "2"),
    )

    def run(self, case=None, **kwargs):
        for case in self.get_cases(case, kwargs):
            rows, columns = case
            tags = {"rows": rows, "columns": columns}
            func = self._get_benchmark_function(rows, columns)
            benchmark, output = self.conbench.benchmark(
                func,
                self.name,
                tags=tags,
                options=kwargs,
            )
            yield benchmark, output

    def _get_benchmark_function(self, rows, columns):
        return lambda: int(rows) * [int(columns) * [0]]

(conbench) $ cd ~/workspace/conbench/conbench/tests/benchmark/
(conbench) $ conbench matrix --help

Usage: conbench matrix [OPTIONS]

  Run matrix benchmark(s).

  For each benchmark option, the first option value is the default.

  Valid benchmark combinations:
  --rows=10 --columns=10
  --rows=2 --columns=10
  --rows=10 --columns=2

  To run all combinations:
  $ conbench matrix --all=true

Options:
  --rows [10|2]
  --columns [10|2]
  --all BOOLEAN          [default: false]
  --iterations INTEGER   [default: 1]
  --drop-caches BOOLEAN  [default: false]
  --gc-collect BOOLEAN   [default: true]
  --gc-disable BOOLEAN   [default: true]
  --show-result BOOLEAN  [default: true]
  --show-output BOOLEAN  [default: false]
  --run-id TEXT          Group executions together with a run id.
  --run-name TEXT        Name of run (commit, pull request, etc).
  --help                 Show this message and exit.
    """

Note that the use of --all=true results in 3 benchmark results, one for each case (10 x 10, 2, x 10, and 10, x 2).

(conbench) $ cd ~/workspace/conbench/conbench/tests/benchmark/
(conbench) $ conbench matrix --all=true

Benchmark result:
{
    "run_id": "d509f6e80ed440a09af60fe1847dc033",
    "batch_id": "d509f6e80ed440a09af60fe1847dc033",
    "timestamp": "2021-06-22T18:39:53.805714+00:00",
    "context": {
        "benchmark_language": "Python",
        "benchmark_language_version": "Python 3.9.2"
    },
    "github": {
        "commit": "58fb35dc593dca82c917cf18c1c65c059b9fb12c",
        "repository": "https://github.com/conbench/conbench"
    },
    "machine_info": {
        "architecture_name": "x86_64",
        "cpu_core_count": "2",
        "cpu_frequency_max_hz": "3500000000",
        "cpu_l1d_cache_bytes": "32768",
        "cpu_l1i_cache_bytes": "32768",
        "cpu_l2_cache_bytes": "262144",
        "cpu_l3_cache_bytes": "4194304",
        "cpu_model_name": "Intel(R) Core(TM) i7-7567U CPU @ 3.50GHz",
        "cpu_thread_count": "4",
        "kernel_name": "20.5.0",
        "memory_bytes": "17179869184",
        "name": "machine-abc",
        "os_name": "macOS",
        "os_version": "10.16"
    },
    "stats": {
        "data": [
            "0.000010"
        ],
        "iqr": "0.000000",
        "iterations": 1,
        "max": "0.000010",
        "mean": "0.000010",
        "median": "0.000010",
        "min": "0.000010",
        "q1": "0.000010",
        "q3": "0.000010",
        "stdev": 0,
        "time_unit": "s",
        "times": [],
        "unit": "s"
    },
    "tags": {
        "columns": "10",
        "name": "matrix",
        "rows": "10"
    }
}

Benchmark result:
{
    "run_id": "d509f6e80ed440a09af60fe1847dc033",
    "batch_id": "d509f6e80ed440a09af60fe1847dc033",
    "timestamp": "2021-06-22T18:39:53.830928+00:00",
    "context": {
        "benchmark_language": "Python",
        "benchmark_language_version": "Python 3.9.2"
    },
    "github": {
        "commit": "58fb35dc593dca82c917cf18c1c65c059b9fb12c",
        "repository": "https://github.com/conbench/conbench"
    },
    "machine_info": {
        "architecture_name": "x86_64",
        "cpu_core_count": "2",
        "cpu_frequency_max_hz": "3500000000",
        "cpu_l1d_cache_bytes": "32768",
        "cpu_l1i_cache_bytes": "32768",
        "cpu_l2_cache_bytes": "262144",
        "cpu_l3_cache_bytes": "4194304",
        "cpu_model_name": "Intel(R) Core(TM) i7-7567U CPU @ 3.50GHz",
        "cpu_thread_count": "4",
        "kernel_name": "20.5.0",
        "memory_bytes": "17179869184",
        "name": "machine-abc",
        "os_name": "macOS",
        "os_version": "10.16"
    },
    "stats": {
        "data": [
            "0.000006"
        ],
        "iqr": "0.000000",
        "iterations": 1,
        "max": "0.000006",
        "mean": "0.000006",
        "median": "0.000006",
        "min": "0.000006",
        "q1": "0.000006",
        "q3": "0.000006",
        "stdev": 0,
        "time_unit": "s",
        "times": [],
        "unit": "s"
    },
    "tags": {
        "columns": "10",
        "name": "matrix",
        "rows": "2"
    }
}

Benchmark result:
{
    "run_id": "d509f6e80ed440a09af60fe1847dc033",
    "batch_id": "d509f6e80ed440a09af60fe1847dc033",
    "timestamp": "2021-06-22T18:39:53.843815+00:00",
    "context": {
        "benchmark_language": "Python",
        "benchmark_language_version": "Python 3.9.2"
    },
    "github": {
        "commit": "58fb35dc593dca82c917cf18c1c65c059b9fb12c",
        "repository": "https://github.com/conbench/conbench"
    },
    "machine_info": {
        "architecture_name": "x86_64",
        "cpu_core_count": "2",
        "cpu_frequency_max_hz": "3500000000",
        "cpu_l1d_cache_bytes": "32768",
        "cpu_l1i_cache_bytes": "32768",
        "cpu_l2_cache_bytes": "262144",
        "cpu_l3_cache_bytes": "4194304",
        "cpu_model_name": "Intel(R) Core(TM) i7-7567U CPU @ 3.50GHz",
        "cpu_thread_count": "4",
        "kernel_name": "20.5.0",
        "memory_bytes": "17179869184",
        "name": "machine-abc",
        "os_name": "macOS",
        "os_version": "10.16"
    },
    "stats": {
        "data": [
            "0.000007"
        ],
        "iqr": "0.000000",
        "iterations": 1,
        "max": "0.000007",
        "mean": "0.000007",
        "median": "0.000007",
        "min": "0.000007",
        "q1": "0.000007",
        "q3": "0.000007",
        "stdev": 0,
        "time_unit": "s",
        "times": [],
        "unit": "s"
    },
    "tags": {
        "columns": "2",
        "name": "matrix",
        "rows": "10"
    }
}

Example R benchmarks

Here are a few examples illustrating how to integrate R benchmarks with Conbench.

The first one just times 1 + 1 in R, and the second one executes an R benchmark from a library of R benchmarks (in this case arrowbench).

If you find yourself wrapping a lot of R benchmarks in Python to integrate them with Conbench (to get uniform JSON benchmark results which you can persist and publish on a Conbench server), you'll probably want to extract much of the boilerplate out into a base class.

import conbench.runner


@conbench.runner.register_benchmark
class ExternalBenchmarkR(conbench.runner.Benchmark):
    """Example benchmark that records an R benchmark result."""

    external = True
    name = "external-r"

    def run(self, **kwargs):
        result, output = self._run_r_command()
        yield self.conbench.record(
            {"data": [result], "unit": "s"},
            self.name,
            context=self.conbench.r_info,
            options=kwargs,
            output=output,
        )

    def _run_r_command(self):
        output, _ = self.conbench.execute_r_command(self._get_r_command())
        result = float(output.split("\n")[-1].split("[1] ")[1])
        return result, output

    def _get_r_command(self):
        return (
            f"addition <- function() { 1 + 1 }; "
            f"start_time <- Sys.time();"
            f"addition(); "
            f"end_time <- Sys.time(); "
            f"result <- end_time - start_time; "
            f"as.numeric(result); "
        )

(conbench) $ cd ~/workspace/conbench/conbench/tests/benchmark/
(conbench) $ conbench external-r --help

Usage: conbench external-r [OPTIONS]

  Run external-r benchmark.

Options:
  --show-result BOOLEAN  [default: true]
  --show-output BOOLEAN  [default: false]
  --run-id TEXT          Group executions together with a run id.
  --run-name TEXT        Name of run (commit, pull request, etc).
  --help                 Show this message and exit.

import json

import conbench.runner


@conbench.runner.register_benchmark
class ExternalBenchmarkOptionsR(conbench.runner.Benchmark):
    """Example benchmark that records an R benchmark result (with options)."""

    external = True
    name = "external-r-options"
    options = {
        "iterations": {"default": 1, "type": int},
        "drop_caches": {"type": bool, "default": "false"},
    }

    def run(self, **kwargs):
        data, iterations = [], kwargs.get("iterations", 1)

        for _ in range(iterations):
            if kwargs.get("drop_caches", False):
                self.conbench.sync_and_drop_caches()
            result, output = self._run_r_command()
            data.append(result["result"][0]["real"])

        yield self.conbench.record(
            {"data": data, "unit": "s"},
            self.name,
            context=self.conbench.r_info,
            options=kwargs,
            output=output,
        )

    def _run_r_command(self):
        r_command = self._get_r_command()
        self.conbench.execute_r_command(r_command)
        with open('placebo.json') as json_file:
            data = json.load(json_file)
        return data, json.dumps(data, indent=2)

    def _get_r_command(self):
        return (
            f"library(arrowbench); "
            f"out <- run_one(arrowbench:::placebo); "
            f"cat(jsonlite::toJSON(out), file='placebo.json'); "
        )

(conbench) $ cd ~/workspace/conbench/conbench/tests/benchmark/
(conbench) $ conbench external-r --help

Usage: conbench external-r-options [OPTIONS]

  Run external-r-options benchmark.

Options:
  --iterations INTEGER   [default: 1]
  --drop-caches BOOLEAN  [default: false]
  --show-result BOOLEAN  [default: true]
  --show-output BOOLEAN  [default: false]
  --run-id TEXT          Group executions together with a run id.
  --run-name TEXT        Name of run (commit, pull request, etc).
  --help                 Show this message and exit.