ChatterBox.Client.Voip.Utils.CPUData.GetCPUUsage C# (CSharp) Method

        public static double GetCPUUsage() 
        {

            double ret = 0.0;

            //retrieve process time
            ProcessTimes processTimes = GetProcessTimes();

            UInt64 currentProcessTime = processTimes.KernelTime + processTimes.UserTime;

            //retrieve system time
            // get number of CPU cores, then, check system time for every CPU core
            if(numberOfProcessors == 0 )
            {
                SystemInfo info;
                GetSystemInfo(out info);

                Debug.WriteLine(info.NumberOfProcessors);

                numberOfProcessors = info.NumberOfProcessors;
            }

            int size =System.Runtime.InteropServices.Marshal.SizeOf<SYSTEM_PROCESSOR_PERFORMANCE_INFORMATION>();

            size = (int) (size * numberOfProcessors);

            IntPtr systemProcessInfoBuff = Marshal.AllocHGlobal(size); // should be more than adequate
            uint length = 0;
            NtStatus result = NtQuerySystemInformation(SYSTEM_INFORMATION_CLASS.SystemProcessorPerformanceInformation, systemProcessInfoBuff, (uint)size, out length);

            if (result != NtStatus.Success)
            {
                Debug.WriteLine($"Failed to obtain processor performance information ({result})");
                return ret;
            }
            UInt64 currentSystemTime = 0;
            var systemProcInfoData = systemProcessInfoBuff;
            for (int i = 0; i < numberOfProcessors; i++)
            {
                SYSTEM_PROCESSOR_PERFORMANCE_INFORMATION processPerInfo = (SYSTEM_PROCESSOR_PERFORMANCE_INFORMATION)Marshal.PtrToStructure<SYSTEM_PROCESSOR_PERFORMANCE_INFORMATION>(systemProcInfoData);

                currentSystemTime += processPerInfo.KernelTime + processPerInfo.UserTime;
            }

            //we need to at least measure twice 
            if (previousProcessTime != 0 && previousSystemTIme != 0)
            {
                ret = ((double)(currentProcessTime - previousProcessTime) / (double)(currentSystemTime - previousSystemTIme)) * 100.0;
            }

            previousProcessTime = currentProcessTime;

            previousSystemTIme = currentSystemTime;

            Debug.WriteLine($"CPU usage: {ret}%");

            return ret;
        }