# Configuring Blackfire Continuous Profiler for Rust

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[configuring continuous profiling](https://www.youtube-nocookie.com/embed/1q_E6fk2Q1Q?rel=0&showinfo=0&modestbranding=1&autoplay=0)

The Rust continuous profiling is currently made across 3 dimensions:

- **Allocations**: Number of objects allocated
- **Allocated Memory**: Number of bytes allocated
- **CPU**: Time spent running on the CPU

## Requirements

- Linux (`glibc` or `musl`)
- [Blackfire Agent](../up-and-running/configuration/agent) >= 2.13.0

## Installation

1. Download the latest [ddprof release](https://github.com/DataDog/ddprof/releases).

    > ```bash
    > curl -Lo ddprof https://github.com/DataDog/ddprof/releases/latest/download/ddprof-<ARCH>
    > mv ddprof INSTALLATION_TARGET
    > ```
    >
    >
    >
    > `INSTALLATION_TARGET` specifies the designated location to store the ddprof binary. The examples bellow assume `INSTALLATION_TARGET` is set to `./ddprof`.

    > **Note**
    >
    > Blackfire utilizes the open source Datadog profiler to collect continuous profiling traces and, via its [agent](../reference-guide/glossary#term-agent), sends it directly to Blackfire's ingesters where we process and analyze the data for your observability needs.
2. Enable the Rust Continuous Profiler by defining these environment variables:

    - `DD_PROFILING_ENABLED=true`: controls the activation of the continuous profiler.
    - `DD_SERVICE=my-rust-app`: sets the application name.
    - **`DD_TRACE_AGENT_URL=unix:///var/run/blackfire/agent.sock`: has Blackfire**

         Agent collect traces.
3. Modify your service invocation to include the continuous profiler. Your usual command is passed as the last arguments to the `ddprof` executable.

    ```bash
    ./ddprof myrustapp --arg1 --arg2
    
    # using a shell builtin
    exec ./ddprof myrustapp --arg1 --arg2
    ```

There is also some additional configuration that can be done using environment variables:

- `BLACKFIRE_LOG_FILE`: Sets the log file. The default is logging to `stderr`.
- `BLACKFIRE_LOG_LEVEL`: Sets the log level. The default is logging only errors.