Looking At The Performance Overhead Of A Read-Only Lock In Lucee CFML 5.3.8.201

core-count.cfm

<cfscript>

	coreCount = createObject( "java", "java.lang.Runtime" )
		.getRuntime()
		.availableProcessors()
	;

	dump( coreCount );

</cfscript>

with-lock-out.txt

With-lock test
Loop Counter: 5263
Value Counter: 10491977

With-lock test
Loop Counter: 4939
Value Counter: 9835909

With-lock test
Loop Counter: 5045
Value Counter: 10060834

With-lock test
Loop Counter: 5358
Value Counter: 10688017

With-lock test
Loop Counter: 5642
Value Counter: 11256738

with-lock.cfm

<cfscript>

	// Let's attempt to simulate concurrent request activity all trying to access shared
	// data. Each entry in the simulated request will be executed via parallel iteration.
	// And, each parallel iteration will try to iterate over the given shared data array.
	simulatedRequests = buildArray( 20 );
	sharedData = buildArray( 100 );

	// Let's keep track of how many test iterations we perform in our test window.
	loopCounter = 0;
	valueCounter = 0;

	// Each test window will be 10-seconds long.
	cutoffAt = ( getTickCount() + ( 10 * 1000 ) );

	// Let's see how many contentious read operations we can perform in our test window.
	while ( getTickCount() < cutoffAt ) {

		simulatedRequests.each(
			() => {

				lock
					name = "read-only-lock-test"
					type = "readonly"
					timeout = 5
					{

					for ( var increment in sharedData ) {

						// CAUTION: The "++" operator is NOT THREAD SAFE. As such, we
						// cannot trust the following operation inside a parallel
						// iterator. That said, I have it here in order to make sure that
						// the Lucee compiler doesn't try to optimize this inner loop
						// away. I wanted to make sure that we're consuming the iteration
						// value in some way.
						valueCounter += increment;

					}

				}

			},
			// Run the .each() in parallel using Java's thread pool.
			true,
			// Maximum number of parallel threads.
			simulatedRequests.len()
		);

		loopCounter++;

	};

	echo( "With-lock test <br />" );
	echo( "Loop Counter: #loopCounter.intValue()# <br />" );
	echo( "Value Counter: #valueCounter.intValue()# <br />" );

	// ------------------------------------------------------------------------------- //
	// ------------------------------------------------------------------------------- //

	/**
	* I construct an array of the given size in each value is "1".
	*/
	public array function buildArray( required numeric size ) {

		var result = [];

		for ( var i = 1 ; i <= size ; i++ ) {

			result[ i ] = 1; // All values are 1 (for our counter).

		}

		return( result );

	}

</cfscript>

without-lock-out.txt

Without-lock test
Loop Counter: 5397
Value Counter: 10769762

Without-lock test
Loop Counter: 4964
Value Counter: 9895341

Without-lock test
Loop Counter: 5138
Value Counter: 10242939

Without-lock test
Loop Counter: 5296
Value Counter: 10552607

Without-lock test
Loop Counter: 4885
Value Counter: 9740710

without-lock.cfm

<cfscript>

	// Let's attempt to simulate concurrent request activity all trying to access shared
	// data. Each entry in the simulated request will be executed via parallel iteration.
	// And, each parallel iteration will try to iterate over the given shared data array.
	simulatedRequests = buildArray( 20 );
	sharedData = buildArray( 100 );

	// Let's keep track of how many test iterations we perform in our test window.
	loopCounter = 0;
	valueCounter = 0;

	// Each test window will be 10-seconds long.
	cutoffAt = ( getTickCount() + ( 10 * 1000 ) );

	// Let's see how many contentious read operations we can perform in our test window.
	while ( getTickCount() < cutoffAt ) {

		simulatedRequests.each(
			() => {

				for ( var increment in sharedData ) {

					// CAUTION: The "++" operator is NOT THREAD SAFE. As such, we cannot
					// trust the following operation inside a parallel iterator. That
					// said, I have it here in order to make sure that the Lucee compiler
					// doesn't try to optimize this inner loop away. I wanted to make sure
					// that we're consuming the iteration value in some way.
					valueCounter += increment;

				}

			},
			// Run the .each() in parallel using Java's thread pool.
			true,
			// Maximum number of parallel threads.
			simulatedRequests.len()
		);

		loopCounter++;

	}

	echo( "Without-lock test <br />" );
	echo( "Loop Counter: #loopCounter# <br />" );
	echo( "Value Counter: #valueCounter.intValue()# <br />" );

	// ------------------------------------------------------------------------------- //
	// ------------------------------------------------------------------------------- //

	/**
	* I construct an array of the given size in each value is "1".
	*/
	public array function buildArray( required numeric size ) {

		var result = [];

		for ( var i = 1 ; i <= size ; i++ ) {

			result[ i ] = 1; // All values are 1 (for our counter).

		}

		return( result );

	}

</cfscript>