Enabling the Ruby Profiler

The profiler is shipped within Datadog tracing libraries. If you are already using APM to collect traces for your application, you can skip installing the library and go directly to enabling the profiler.

Requirements

For a summary of the minimum and recommended runtime and tracer versions across all languages, read Supported Language and Tracer Versions.

The Datadog Profiler requires Ruby 2.5+. JRuby and TruffleRuby are not supported.

The following operating systems and architectures are supported:

  • Linux (GNU libc) x86-64, aarch64
  • Alpine Linux (musl libc) x86-64, aarch64

You also need either the pkg-config or the pkgconf system utility installed. This utility is available on the software repositories of most Linux distributions. For example:

  • The pkg-config package is available for Homebrew, and Debian- and Ubuntu-based Linux
  • The pkgconf package is available for Arch- and Alpine-based Linux
  • The pkgconf-pkg-config package is available for Fedora- and Red-Hat-based Linux

Continuous Profiler is not supported on serverless platforms, such as AWS Lambda.

Single Step Instrumentation is not supported for Linux hosts, VMs, or Docker. Single Step Instrumentation is supported for Kubernetes (using the Datadog Helm chart), but you need to manually set the DD_PROFILING_ENABLED=true environment variable to enable profiling.

Installation

To begin profiling applications:

  1. Ensure Datadog Agent v6+ is installed and running. Datadog recommends using Datadog Agent v7+.

  2. Add the datadog gem to your Gemfile or gems.rb file:

    gem 'datadog', '~> 2.3'

  3. Install the gems with bundle install.

  4. Enable the profiler:

      export DD_PROFILING_ENABLED=true
export DD_ENV=prod
export DD_SERVICE=my-web-app
export DD_VERSION=1.0.3

      Datadog.configure do |c|
  c.profiling.enabled = true
  c.env = 'prod'
  c.service = 'my-web-app'
  c.version = '1.0.3'
end

      Note: For Rails applications, create a config/initializers/datadog.rb file with the code configuration above.

    • Add the ddprofrb exec command to your Ruby application start command:

      bundle exec ddprofrb exec ruby myapp.rb

      Rails example:

      bundle exec ddprofrb exec bin/rails s

      If you’re running a version of the gem older than 1.21.0, replace ddprofrb exec with ddtracerb exec.

      Note

      If starting the application with ddprofrb exec is not an option (for example, when using the Phusion Passenger web server), you can alternatively start the profiler by adding the following to your application entry point (such as config.ru, for a web application):

      require 'datadog/profiling/preload'

    • Optional: Set up Source Code Integration to connect your profiling data with your Git repositories.

    • A minute or two after starting your Ruby application, your profiles will show up on the Datadog APM > Profiler page.

    Configuration

    These settings apply to the latest profiler release.

    You can configure the profiler using the following environment variables:

    Environment variableTypeDescription
    DD_PROFILING_ENABLEDBooleanIf set to true, enables the profiler. Defaults to false.
    DD_PROFILING_ALLOCATION_ENABLEDBooleanSet to true to enable allocation profiling. It requires the profiler to be enabled already. Defaults to false.
    DD_PROFILING_EXPERIMENTAL_HEAP_ENABLEDBooleanSet to true to enable heap live objects profiling. It requires that allocation profiling is enabled as well. Defaults to false.
    DD_PROFILING_EXPERIMENTAL_HEAP_SIZE_ENABLEDBooleanSet to true to enable heap live size profiling. It requires that heap live objects profiling is enabled as well. Defaults to false.
    DD_PROFILING_NO_SIGNALS_WORKAROUND_ENABLEDBooleanAutomatically enabled when needed, can be used to force enable or disable this feature. See Profiler Troubleshooting for details.
    DD_ENVStringThe environment name, for example: production.
    DD_SERVICEStringThe service name, for example, web-backend.
    DD_VERSIONStringThe version of your service.
    DD_TAGSStringTags to apply to an uploaded profile. Must be a list of <key>:<value> separated by commas such as: layer:api, team:intake.

    Alternatively, you can set profiler parameters in code with these functions, inside a Datadog.configure block:

    Environment variableTypeDescription
    c.profiling.enabledBooleanIf set to true, enables the profiler. Defaults to false.
    c.profiling.allocation_enabledBooleanSet to true to enable allocation profiling. It requires the profiler to be enabled already. Defaults to false.
    c.profiling.advanced.experimental_heap_enabledBooleanSet to true to enable heap live objects profiling. It requires that allocation profiling is enabled as well. Defaults to false.
    c.profiling.advanced.experimental_heap_size_enabledBooleanSet to true to enable heap live size profiling. It requires that heap live objects profiling is enabled as well. Defaults to false.
    c.profiling.advanced.no_signals_workaround_enabledBooleanAutomatically enabled when needed, can be used to force enable or disable this feature. See Profiler Troubleshooting for details.
    c.envStringThe environment name, for example: production.
    c.serviceStringThe service name, for example, web-backend.
    c.versionStringThe version of your service.
    c.tagsHashTags to apply to an uploaded profile.

    Not sure what to do next?

    The Getting Started with Profiler guide takes a sample service with a performance problem and shows you how to use Continuous Profiler to understand and fix the problem.

    Further Reading

    Additional helpful documentation, links, and articles:

    Getting Started with ProfilerDOCUMENTATION more more Learn more about available profile visualizationsDOCUMENTATION more more Fix problems you encounter while using the profilerDOCUMENTATION more more Analyze Ruby code performance with Datadog Continuous ProfilerBLOG more more