> ## Documentation Index
> Fetch the complete documentation index at: https://mintlify.com/dotandev/hintents/llms.txt
> Use this file to discover all available pages before exploring further.

# erst profile

> Export trace as pprof profile for gas-to-function mapping

Synthesize trace events into a pprof-compliant profile that maps gas consumption to functions.

## Usage

```bash theme={null}
erst profile [trace-file] [flags]
```

## Description

The `profile` command converts Erst execution traces into the pprof profile format, which can be analyzed using Go's profiling tools. This allows you to:

* Map gas consumption to specific functions
* Identify performance bottlenecks
* Analyze call graphs and hotspots
* Generate flamegraphs with standard tooling

<Info>
  The output is compatible with `go tool pprof` and other pprof-compatible analyzers.
</Info>

## Examples

<CodeGroup>
  ```bash Basic usage theme={null}
  erst profile execution.json -o gas.pb.gz
  ```

  ```bash Using file flag theme={null}
  erst profile --file debug_trace.json -o gas.pb.gz
  ```

  ```bash Analyze with pprof theme={null}
  erst profile execution.json -o gas.pb.gz
  go tool pprof gas.pb.gz
  ```

  ```bash Generate flamegraph theme={null}
  erst profile execution.json -o gas.pb.gz
  go tool pprof -http=:8080 gas.pb.gz
  ```
</CodeGroup>

## Arguments

<ParamField path="trace-file" type="string">
  Path to the trace file to convert (JSON format)

  Can be provided as positional argument or via `--file` flag.
</ParamField>

## Flags

<ParamField path="--file" type="string">
  Trace file to load (alternative to positional argument)

  Alias: `-f`
</ParamField>

<ParamField path="--output" type="string" default="profile.pb.gz">
  Output pprof file path

  Alias: `-o`
</ParamField>

## Output format

The generated profile file is a gzip-compressed protobuf that contains:

* **Sample data**: Gas consumption per function call
* **Call stacks**: Complete execution paths
* **Location info**: Function names and contract addresses
* **Metadata**: Transaction hash, network, and timestamps

## Analyzing profiles

Once you've generated a profile, use these commands to analyze it:

### Interactive web UI

```bash theme={null}
go tool pprof -http=:8080 gas.pb.gz
```

This launches a web interface with:

* Interactive flamegraph
* Call graph visualization
* Source code view (if debug symbols available)
* Top functions by gas consumption

### Command-line analysis

<Tabs>
  <Tab title="Top functions">
    ```bash theme={null}
    go tool pprof -top gas.pb.gz
    ```

    Shows functions sorted by gas consumption.
  </Tab>

  <Tab title="Call graph">
    ```bash theme={null}
    go tool pprof -tree gas.pb.gz
    ```

    Displays hierarchical call tree.
  </Tab>

  <Tab title="Flamegraph">
    ```bash theme={null}
    go tool pprof -raw gas.pb.gz | flamegraph.pl > flame.svg
    ```

    Generates SVG flamegraph (requires flamegraph.pl).
  </Tab>

  <Tab title="Focus on function">
    ```bash theme={null}
    go tool pprof -focus=transfer gas.pb.gz
    ```

    Filters to specific function and callers/callees.
  </Tab>
</Tabs>

## Use cases

### Optimize gas consumption

Identify which functions consume the most gas:

```bash theme={null}
erst profile execution.json -o gas.pb.gz
go tool pprof -top10 gas.pb.gz
```

### Compare optimizations

Generate profiles before and after optimization:

```bash theme={null}
# Before
erst profile before.json -o before.pb.gz

# After
erst profile after.json -o after.pb.gz

# Compare
go tool pprof -base=before.pb.gz after.pb.gz
```

### Debug performance issues

Find unexpected bottlenecks:

```bash theme={null}
erst profile execution.json -o gas.pb.gz
go tool pprof -http=:8080 gas.pb.gz
# Click "Flame Graph" in web UI
```

## Related commands

* [trace](/commands/trace) - View traces interactively
* [debug](/commands/debug) - Generate traces from transactions
* [compare](/commands/compare) - Compare gas usage between versions