Display cpu performance with DynamicDataDisplay

Inspired by this blog. I want to plot each processor's performance. After add DynamicDataDisplay from Nuget. So the xaml code.

<Window x:Class="CPU_Performance.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:d3="http://research.microsoft.com/DynamicDataDisplay/1.0"
        xmlns:local="clr-namespace:CPU_Performance"
        mc:Ignorable="d"
        Title="MainWindow" Loaded="Window_Loaded" Height="350" Width="525"><Grid><Grid.RowDefinitions><RowDefinition Height="Auto"/><RowDefinition Height="*"/></Grid.RowDefinitions><StackPanel Orientation="Horizontal"><TextBlock Text="CPU Usage" Margin="20,10,0,0"
                       FontSize="15" FontWeight="Bold"/><TextBlock x:Name="cpuUsageText" Margin="10,10,0,0"
                       FontSize="15"/></StackPanel><d3:ChartPlotter x:Name="plotter" Margin="10,10,20,10" Grid.Row="1"><d3:ChartPlotter.VerticalAxis><d3:VerticalIntegerAxis /></d3:ChartPlotter.VerticalAxis><d3:ChartPlotter.HorizontalAxis><d3:HorizontalIntegerAxis /></d3:ChartPlotter.HorizontalAxis><d3:Header Content="CPU Performance History"/><d3:VerticalAxisTitle Content="Percentage"/></d3:ChartPlotter></Grid></Window>

And the cs code is:

using Microsoft.Research.DynamicDataDisplay;
using Microsoft.Research.DynamicDataDisplay.DataSources;
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Media;
using System.Windows.Threading;

namespace CPU_Performance
{
    public partial class MainWindow : Window
    {
        private ObservableDataSource<Point> dataSource = new ObservableDataSource<Point>();
        private PerformanceCounter[] cpuPerformance = new PerformanceCounter[System.Environment.ProcessorCount];
        private DispatcherTimer timer = new DispatcherTimer();
        private int i = 0;

        public MainWindow()
        {
            InitializeComponent();
        }
        private async void AnimatedPlot(object sender, EventArgs e)
        {
            var t = new Task[cpuPerformance.Length];
            for (int j = 0; j < cpuPerformance.Length; j++)
            {
                t[j] = new Task(()=>
                {
                    cpuPerformance[j] = new PerformanceCounter("Processor", "% Processor Time", j.ToString());
                    double x = i;
                    double y = cpuPerformance[j].NextValue();

                    Point point = new Point(x, y);
                    dataSource.AppendAsync(base.Dispatcher, point);

                    cpuUsageText.Text = String.Format("{0:0}%", y);
                    i++;
                }
                );
            }
            await Task.WhenAll(t);
        }

        private void Window_Loaded(object sender, RoutedEventArgs e)
        {
            plotter.AddLineGraph(dataSource, Colors.Green, 2, "Percentage");
            timer.Interval = TimeSpan.FromSeconds(1);
            timer.Tick += new EventHandler(AnimatedPlot);
            timer.IsEnabled = true;
            plotter.Viewport.FitToView();
        }
    }
}