timer_float() │ WP 5.8.0

Let's see how the function works if it is called several times:

var_dump( timer_float() );  // float(0.069790124893188)

sleep( 1 );

var_dump( timer_float() );  // float(1.0698711872101)

An example of how to format the result of a function into a normal human form.

$timer = timer_float();

printf( 'Passed %.4F sec.', $timer ); //> It has been 0.1347 sec.

This function gives us the time from when PHP is running and timer_stop() from when WP core is running, which means we can calculate the difference and see how much time passes before WP itself starts.

if( isset( $_GET['check_time'] ) ){
	add_filter( 'init', 'my_check_time', PHP_INT_MAX );
}

function my_check_time(){

	$timer_float = timer_float();
	$timer_stop = timer_stop( 0, 15 );

	var_dump( $timer_float ); //       float(0.036677122116089)
	var_dump( $timer_stop );  // string(17) "0.034716844558716"

	var_dump( $timer_float - (float) $timer_stop );  // float(0.0019602775573729)

	exit;
}

As you can see, from the start of PHP to the start of WP, it takes 0.00196 seconds. I thought it would be much faster 🙁

I ran this code on the local WordPress 5.9.

On the wp_loaded hook you can say that the entire WP core is loaded, but no database queries have yet been made to handle the current URL request.

if( isset( $_GET['check_time'] ) ){
	add_filter( 'wp_loaded', 'my_check_time', PHP_INT_MAX );
}

function my_check_time(){

	var_dump( timer_float() );  // float(0.035823106765747)

	exit;
}

As you can see it took 0.0358 seconds to load the WP kernel since PHP was running.

I ran this code on a local WordPress 5.9 (bare installation without plugins)

Display it all in the footer of the site (in the front) and in the footer of the admin panel:

/**
 * Outputs data about the number of queries to the database,
 * the script execution time and the amount of memory used.
 */
add_filter( 'wp_footer', 'wp_usage' ); // on the site
add_filter( 'admin_footer_text', 'wp_usage' ); // in the admin

function wp_usage(){

	echo sprintf(
		'SQL: %d for %.3F sec. %s MB',
		get_num_queries(),
		timer_float(),
		round( memory_get_peak_usage()/1024/1024, 2 )
	);
}

For this operation, we don't need any WP helper functions. The native PHP function microtime() is enough here.

Let's measure how long the get_posts() function takes to retrieve the posts:

$time_start = microtime( true );

// the code, the execution time of which is measured
get_posts();

$diff = sprintf( '%.7f', microtime( true ) - $time_start );

echo "get_posts() worked $diff seconds";

/*
 we get:
 get_posts() worked for 0.0030319690704346 seconds
 */