evalFuncOpt.js

/**
 * Test V8 optimization against eval and new Function
 * Run with: node --allow-natives-syntax evalFuncOpt.js
 * More verbose with: node --trace_opt --trace_deopt --allow-natives-syntax evalFuncOpt.js
 * 
 * More info at: https://github.com/petkaantonov/bluebird/wiki/Optimization-killers
 */

var b = 0;
function getStatus(fn) {
    const flags = [];
    const vs = %GetOptimizationStatus(fn);
    if (vs & (1 << 0)) flags.push('kIsFunction');
    if (vs & (1 << 1)) flags.push('kNeverOptimize');
    if (vs & (1 << 2)) flags.push('kAlwaysOptimize');
    if (vs & (1 << 3)) flags.push('kMaybeDeopted');
    if (vs & (1 << 4)) flags.push('kOptimized');
    if (vs & (1 << 5)) flags.push('kTurboFanned');
    if (vs & (1 << 6)) flags.push('kInterpreted');
    if (vs & (1 << 7)) flags.push('kMarkedForOptimization');
    if (vs & (1 << 8)) flags.push('kMarkedForConcurrentOptimization');
    if (vs & (1 << 9)) flags.push('kOptimizingConcurrently');
    if (vs & (1 << 10)) flags.push('kIsExecuting');
    if (vs & (1 << 11)) flags.push('kTopmostFrameIsTurboFanned');
    if (vs & (1 << 12)) flags.push('kLiteMode');
    if (vs & (1 << 13)) flags.push('kMarkedForDeoptimization');
    if (vs & (1 << 14)) flags.push('kBaseline');
    if (vs & (1 << 15)) flags.push('kTopmostFrameIsInterpreted');
    if (vs & (1 << 16)) flags.push('kTopmostFrameIsBaseline');
    return flags.join(', ');
}

const HOT_ITERS = 100_000_000;
function performTest(fn, desc) {
    console.log(`\x1B[33m==> Testing Function: ${desc}\x1B[0m`);

    // Warmup.
    console.log("Before Call", getStatus(fn));
    fn(0, 1);
    fn(2, 3);

    // Force optimization.
    console.log("Before Optimization", getStatus(fn));
    %OptimizeFunctionOnNextCall(fn);
    fn(3, 4);

    // Force hot loop optimization.
    console.log("Before Hot", getStatus(fn));
    for (let i = 0; i < HOT_ITERS; i++) fn(i, -i);
    
    // After hot loop timization.
    console.log("After Hot", getStatus(fn));

    const start = performance.now();
    for (let i = 0; i < HOT_ITERS; i++) fn(i, -i);
    const end = performance.now();
    console.log("Timings:", (end - start));
    console.log();
}


function adder(a, b) {
    return b%2 ? a + b : b%3 ? a - b : b%5 ? b / a : a * b;
}

const adderFCtor = new Function('a', 'b', 'return b%2 ? a + b : b%3 ? a - b : b%5 ? b / a : a * b');
const adderFEval = eval('(a, b) => { return b%2 ? a + b : b%3 ? a - b : b%5 ? b / a : a * b; }'); 

performTest(adder, "Source");
performTest(adder, "new Function");
performTest(adder, "eval");