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hotpath_macros

Attribute Macro main 

Source 
#[main]
Expand description

Initializes the hotpath profiling system and generates a performance report on program exit.

This attribute macro should be applied to your program’s main (or other entry point) function to enable profiling. It creates a guard that initializes the background measurement processing thread and automatically displays a performance summary when the program exits. Additionally it creates a measurement guard that will be used to measure the wrapper function itself.

§Parameters

  • percentiles - Array of percentile values (0-100) to display in the report. Default: [95]
  • format - Output format as a string: "table" (default), "json", or "json-pretty"
  • limit - Maximum number of functions to display in the report (0 = show all). Default: 15
  • timeout - Optional timeout in milliseconds. If specified, the program will print the report and exit after the timeout.

§Examples

Basic usage with default settings (P95 percentile, table format):

#[hotpath::main]
fn main() {
    // Your code here
}

Custom percentiles:

#[tokio::main]
#[hotpath::main(percentiles = [50, 90, 95, 99])]
async fn main() {
    // Your code here
}

JSON output format:

#[hotpath::main(format = "json-pretty")]
fn main() {
    // Your code here
}

Combined parameters:

#[hotpath::main(percentiles = [50, 99], format = "json")]
fn main() {
    // Your code here
}

Custom limit (show top 20 functions):

#[hotpath::main(limit = 20)]
fn main() {
    // Your code here
}

§Usage with Tokio

When using with tokio, place #[tokio::main] before #[hotpath::main]:

#[tokio::main]
#[hotpath::main]
async fn main() {
    // Your code here
}

§Limitations

Only one hotpath guard can be active at a time. Creating a second guard (either via this macro or via FunctionsGuardBuilder) will cause a panic.

§See Also