此文用于记录测试C#并行处理与单线程执行耗时操作的性能对比
static int count = 100;static Stopwatch sw = new Stopwatch();static void Main(string[] args){Console.WriteLine("Hello, World!");for (int i = 0; i < 5; i++){orderExec();ParallerExec2();Console.ReadLine();}}private static void orderExec(){sw.Restart();var list = Enumerable.Range(0, count).ToList();string imagePath = "E:\\image";string[] iamges = Directory.GetFiles(imagePath).Where(x => x.EndsWith("bmp")).ToArray();for (int i = 0; i < list.Count; i++){DealImage(iamges[i], SKColors.Red, new SKPoint(100, 100));}Console.WriteLine($"执行耗时：{sw.Elapsed.TotalSeconds}");}private static void ParallerExec2()
{int[] numbers = Enumerable.Range(0, count).ToArray(); Stopwatch stopwatch = new Stopwatch();stopwatch.Start();int physicalCoreCount = Environment.ProcessorCount;int parallelCount = physicalCoreCount / 2;Console.WriteLine("虚拟处理器数量:{0}, 并行度：{1}", physicalCoreCount, parallelCount);// 设置并行度var options = new ParallelOptions { MaxDegreeOfParallelism = parallelCount };string imagePath = "E:\\image";string[] iamges = Directory.GetFiles(imagePath).Where(x => x.EndsWith("bmp")).ToArray();Parallel.ForEach(numbers, options, number =>{DealImage(iamges[number],SKColors.Blue, new SKPoint(200, 200));});stopwatch.Stop();Console.WriteLine($"执行耗时: {stopwatch.Elapsed.TotalSeconds}");}private static void DealImage(string file, SKColor color, SKPoint point)
{SKBitmap pic = SKBitmap.Decode(file);SKCanvas canvas = new SKCanvas(pic);canvas.DrawCircle(point.X, point.Y, 100, new SKPaint() { Color = color, Style = SKPaintStyle.Fill });using var stream = File.OpenWrite(file);pic.Encode(SKEncodedImageFormat.Png, 100).SaveTo(stream);stream.Close();stream.Dispose();canvas.Dispose();
}
测试处理100张图（1280x1024）的耗时对比，并行处理的耗时明显比单线程处理的更快，同时并行处理CPU占用会很高，建议设置并行数量时尽量比逻辑处理器个数要少，给其他进程让出部分CPU
