private _trackCpu()

in AutoCollection/Performance.ts [154:221]
45 lines of code
18 McCabe index (conditional complexity)

    private _trackCpu() {
        // this reports total ms spent in each category since the OS was booted, to calculate percent it is necessary
        // to find the delta since the last measurement
        var cpus = os.cpus();
        if (cpus && cpus.length && this._lastCpus && cpus.length === this._lastCpus.length) {
            var totalUser = 0;
            var totalSys = 0;
            var totalNice = 0;
            var totalIdle = 0;
            var totalIrq = 0;
            for (var i = 0; !!cpus && i < cpus.length; i++) {
                var cpu = cpus[i];
                var lastCpu = this._lastCpus[i];

                var name = "% cpu(" + i + ") ";
                var model = cpu.model;
                var speed = cpu.speed;
                var times = cpu.times;
                var lastTimes = lastCpu.times;

                // user cpu time (or) % CPU time spent in user space
                var user = (times.user - lastTimes.user) || 0;
                totalUser += user;

                // system cpu time (or) % CPU time spent in kernel space
                var sys = (times.sys - lastTimes.sys) || 0;
                totalSys += sys;

                // user nice cpu time (or) % CPU time spent on low priority processes
                var nice = (times.nice - lastTimes.nice) || 0;
                totalNice += nice;

                // idle cpu time (or) % CPU time spent idle
                var idle = (times.idle - lastTimes.idle) || 0;
                totalIdle += idle;

                // irq (or) % CPU time spent servicing/handling hardware interrupts
                var irq = (times.irq - lastTimes.irq) || 0;
                totalIrq += irq;
            }

            // Calculate % of total cpu time (user + system) this App Process used (Only supported by node v6.1.0+)
            let appCpuPercent: number = undefined;
            if (typeof (process as any).cpuUsage === 'function') {
                const appCpuUsage = (process as any).cpuUsage();
                const hrtime = process.hrtime();

                const totalApp = ((appCpuUsage.user - this._lastAppCpuUsage.user) + (appCpuUsage.system - this._lastAppCpuUsage.system)) || 0;

                if (typeof this._lastHrtime !== 'undefined' && this._lastHrtime.length === 2) {
                    const elapsedTime = ((hrtime[0] - this._lastHrtime[0]) * 1e6 + (hrtime[1] - this._lastHrtime[1]) / 1e3) || 0; // convert to microseconds

                    appCpuPercent = 100 * totalApp / (elapsedTime * cpus.length);
                }

                // Set previous
                this._lastAppCpuUsage = appCpuUsage;
                this._lastHrtime = hrtime;
            }

            var combinedTotal = (totalUser + totalSys + totalNice + totalIdle + totalIrq) || 1;

            this._client.trackMetric({ name: Constants.PerformanceCounter.PROCESSOR_TIME, value: ((combinedTotal - totalIdle) / combinedTotal) * 100 });
            this._client.trackMetric({ name: Constants.PerformanceCounter.PROCESS_TIME, value: appCpuPercent || ((totalUser / combinedTotal) * 100) });
        }

        this._lastCpus = cpus;
    }