unblocker/test/performance.js

Web proxy for evading internet censorship & general-purpose library for rewriting remote websites.

var fs = require('fs'),
    format = require('util').format,
    concat = require('concat-stream'),
    hyperquest = require('hyperquest'),
    math = require('math-helpers')(),
    async = require('async'),
        getServers = require('./test_utils.js').getServers;

var source = fs.readFileSync(__dirname + '/source/index.html');


// fire up the server and actually run the tests
getServers(source, function(err, servers) {
    // set up the cleanup work first
    //process.on('SIGINT', servers.kill);
    //process.on('SIGTERM', servers.kill);

    var iterations = 1000;
    var concurrency = 30;

    var baseline, proxy;

    new async.series([

            function(next) {
                console.log("\n\n=========\nBaseline\n=========");
                runTest(servers.proxyHome, iterations, concurrency, function(baseFailures, baseSuccesses, time) {
                    baseline = getStats(iterations, baseFailures, baseSuccesses, time);
                    printStats(baseline);
                    next();
                });
            },
            function(next) {
                console.log("\n\n=========\nProxy\n=========");
                runTest(servers.proxiedUrl, iterations, concurrency, function(proxyFailures, proxySuccesses, time) {
                    proxy = getStats(iterations, proxyFailures, proxySuccesses, time);
                    printStats(proxy, baseline);
                    next();
                });
            }
        ],
        function(err) {
            console.log(err || '');
            servers.kill();
        });
});



function runTest(url, iterations, concurrency, cb) {
    var start = Date.now(),
        times = [],
        failures = [],
        tasks = [];

    function addTask() {
        tasks.push(function(step) {
            var start = Date.now();
            hyperquest(url)
                .pipe(concat(function( /*data*/ ) {
                    var time = Date.now() - start;
                    times.push(time);
                    process.stdout.write('.');
                    step();
                }))
                .on('error', function(err) {
                    err.time = Date.now() - start;
                    failures.push(err);
                    process.stdout.write('x');
                    step(err);
                });
        });
    }

    for (var i = 0; i < iterations; i++) {
        addTask();
    }

    async.parallelLimit(tasks, concurrency, function(err) {
        if (err) failures.push(err);
        var totalTime = Date.now() - start;
        cb(failures, times, totalTime);
    });
}

function getStats(iterations, failures, successes, time) {
    var sorted = successes.sort();
    return {
        iterations: iterations,
        failures: failures.length,
        successes: successes.length,
        ms: time,
        average: math.avg(successes),
        stdDev: math.stdDev(successes),
        _50: sorted[Math.round(sorted.length / 2)],
        _75: sorted[Math.round(sorted.length / 4 * 3)],
        _90: sorted[Math.round(sorted.length / 10 * 9)],
        _95: sorted[Math.round(sorted.length / 20 * 19)]
    };
}

function printDifference(stat, proxy, baseline) {
    if (!baseline) return "";
    var percentageDiff = (proxy[stat] * 100 / baseline[stat]) - 100;
    return format("(%s% %s than the baseline)", Math.round(Math.abs(percentageDiff)), (percentageDiff > 0) ? "slower" : "faster");
}

function printStats(stats, baseline) {
    if (stats.failures) {
        console.error(stats.failures + ' failures');
    }
    console.log(format("\n%s/%s iterations completed successfully in %s miliseconds %s",
        stats.successes, stats.iterations, stats.ms, printDifference("ms", stats, baseline)));
    console.log("Average response time: " + stats.average + " miliseconds", printDifference("average", stats, baseline));
    if (baseline) {
        console.log(format("Proxy adds %s ms to each request on average", stats.average - baseline.average));
    }
    console.log("Standard Deviation: " + stats.stdDev,
        printDifference("stdDev", stats, baseline)
        .replace("slower", "worse")
        .replace("faster", "better"));
    console.log(format("Percentile speeds:\n  50%: %sms %s\n  75%: %sms %s\n  90%: %sms %s\n  95%: %sms %s",
        stats._50, printDifference("_50", stats, baseline),
        stats._75, printDifference("_75", stats, baseline),
        stats._90, printDifference("_90", stats, baseline),
        stats._95, printDifference("_95", stats, baseline)));
}