Question

我有一个C＃＆amp;使用GPU（NVIDA GTX980）进行图像处理的.NET应用程序。有4个阶段，我将CPU与GPU同步（时间上没有重叠）来进行计时。但这些数字并没有加起来。

Launch（）将执行GPU内核的异步启动但是同步（）将等到它完成。

总计： tThreshold：4.2827ms

tHistogram：3.7714ms
tHistogramSum：0.1065ms
tIQR：3.8603ms
tThresholdOnly：0.4126ms

发生了什么事？

   public static void threshold()
    {
        Stopwatch watch = new Stopwatch();
        watch.Start();
        gpu.Lock();
        dim3 block = new dim3(tileWidthBig, tileHeightBig);
        dim3 grid = new dim3(Frame.width / tileWidthBig, Frame.height / tileHeightBig);
        gpu.Launch(grid, block).gHistogram(gForeground, gPercentile, gInfo);
        gpu.Synchronize();
        tHistogram = watch.Elapsed.TotalMilliseconds;

        block = new dim3(1024);
        grid = new dim3(1);
        gpu.Launch(grid, block).gSumHistogram(gPercentile);
        gpu.Synchronize();
        tHistogramSum = watch.Elapsed.TotalMilliseconds - tHistogram;

        gpu.Launch(grid, block).gIQR(gPercentile, gInfo);
        gpu.Synchronize();
        tIQR = watch.Elapsed.TotalMilliseconds - tHistogramSum;

        block = new dim3(256, 4);
        grid = new dim3(Frame.width / 256, Frame.height / 4);
        gpu.Launch(grid, block).gThreshold(gForeground, gMask, gInfo);
        gpu.Synchronize();
        tThresholdOnly = watch.Elapsed.TotalMilliseconds - tIQR;

        gpu.Unlock();
        watch.Stop();
        tThreshold = watch.Elapsed.TotalMilliseconds;
    }

Answer 1

由于TotalMilliseconds不断增加＆amp;你试图找出时间点之间的差异，你需要在第二个之后减去前面差异的总和，因此：

tIQR = watch.Elapsed.TotalMillisconds - (tHistogram + tHistogramSum);

＆安培;

tThresholdOnly= watch.Elapsed.TotalMillisconds - (tHistogram + tHistogramSum + tIQR);

来自.net StopWatch的时间不一致

1 个答案: