modules/pathkit/perf/perfReporter.js

const REPORT_URL = 'http://localhost:8081/report_perf_data'
// Set this to enforce that the perf server must be up.
// Typically used for debugging.
const fail_on_no_perf = false;


function benchmarkAndReport(benchName, setupFn, testFn, teardownFn) {
    let ctx = {};
    // warmup 3 times (arbitrary choice)
    setupFn(ctx);
    testFn(ctx);
    testFn(ctx);
    testFn(ctx);
    teardownFn(ctx);

    ctx = {};
    setupFn(ctx);
    let start = Date.now();
    let now = start;
    times = 0;
    // See how many times we can do it in 100ms (arbitrary choice)
    while (now - start < 100) {
        testFn(ctx);
        now = Date.now();
        times++;
    }

    teardownFn(ctx);

    // Try to make it go for 2 seconds (arbitrarily chosen)
    // Since the pre-try took 100ms, multiply by 20 to get
    // approximate tries in 2s
    let goalTimes = times * 20;
    setupFn(ctx);
    start = Date.now();
    times = 0;
    while (times < goalTimes) {
        testFn(ctx);
        times++;
    }
    let end = Date.now();
    teardownFn(ctx);

    let us = (end - start) * 1000 / times;
    console.log(benchName, `${us} microseconds`)
    return _report(us, benchName);
}


function _report(microseconds, benchName) {
    return fetch(REPORT_URL, {
        method: 'POST',
        mode: 'no-cors',
        headers: {
            'Content-Type': 'application/json',
        },
        body: JSON.stringify({
            'bench_name': benchName,
            'time_us': microseconds,
        })
    }).then(() => console.log(`Successfully reported ${benchName} to perf aggregator`));
}

function reportError(done) {
    return (e) => {
        console.log("Error with fetching. Likely could not connect to aggegator server", e.message);
        if (fail_on_no_perf) {
            expect(e).toBeUndefined();
        }
        done();
    };
}