Question

我希望能够计算出我的软件执行查找的速率。该软件正在迭代listbox，其中包含用户名，然后查询我的服务器。我想计算每秒钟我有多少用户名查找？

我是否必须使用每1000米/秒执行计算的计时器？我真的不知道从哪里开始。

我没有任何代码可以显示，只是想得到一些伪代码。

Answer 1

这可能会有所帮助（我真的不知道delphi，因此无法验证语法，它只是每个请求的伪代码）：

var
  // Set a timer and counter variable
  timer : TDateTime;
  rate, counter : Integer;
  n : Integer; // Iterator
begin
  timer := Time;
  counter := 0;

  for n := 0 to list.items.count - 1 do
  begin
    // Do the processing here

    // add 1 to the counter every time you iterate over a username
    counter := counter + 1;
  end;

// Divide Time difference by total to get the rate of username lookups per second
// TDateTime is counted in days, convert it to seconds, to get "per sec" rate
rate := counter / ((Time - timer) * 24 * 60 * 60);

Answer 2

如果你想看到你的程序每秒执行大量的锁定，你可以用TTimer做到这一点。

首先，您需要在循环中设置soume计数器来计算已处理的项目数：

for n := 0 to list.items.count - 1 do
begin
  // Do the processing here

  // add 1 to the counter every time you iterate over a username
  counter := counter + 1;
end;

然后在Timer的OnTimer事件中检查当前计数器状态并输出要标记的状态。最后你将你的计数器重置为零：

procedure TForm1.Timer1Timer(Sender: TObject);
begin
  //read the coutner value to find out how many items was processed
  Label1.Caption := IntToStr(Counter);
  //reset timer to zero
  Counter := 0;
end;

现在，这将为您提供在最后一秒处理了多少项的近似结果。为什么只是近似？ TTimer是基于Windows消息的组件。这意味着它不会保证精度，因此OnTimer事件可能不会在指定的时间间隔内完全触发。我看到偏差甚至高达半秒钟。它很大程度上取决于您的主程序代码和整个系统利用率。

注意：如果您在主程序线程中执行所有这些处理，这种方法将无法工作，因为此类处理可能会锁定您的应用程序，直到循环结束。这意味着您的应用程序不会处理任何基于Windows的消息，包括为了触发定时器OnTimer事件而创建的消息。

在这种情况下，我推荐下一个方法。而不是在一秒钟内测量处理的项目数量，而不是测量处理X项目数量所需的时间。你可以这样做：

const X := 20; //Constant defining how many items needs to be processed 
               //before processing time is evaluated
               //You will need to find out which number of items is best 
               //suitable for you on your own by trial and error.

var 
  //StopWatch is a special record which alows precision timing
  sw: TStopWatch;;
  //Variable for storing elapsed milliseconds of one measuring cycle
  elapsedMilliseconds : cardinal;
  //Estimated number of calculations that would have been processed in one
  //second
  CalculationsPerSecond: Integer;
begin
  counter := 0;
  //Initialize the stop watch
  sw := TStopWatch.Create() ;
  //Start stopwatch
  sw.Start;
  for n := 0 to list.items.count - 1 do
  begin
    // Do the processing here

    // add 1 to the counter every time you iterate over a username
    counter := counter + 1;
    //Check if the counter has been set to specific number of cycles 
    //you want to to measure time taken for
    if Counter = X then
    begin
      //Stop the StopWatch
      sw.Stop;
      //Get how many milliseconds have elapsed since start
      elapsedMilliseconds := sw.ElapsedMilliseconds;
      //Calculate estimated number of items that would have been processed 
      //per second
      CalculationsPerSecond := Round(1000 * X / elapsedMillisecond);
      //Reset counter to zero fopr next cycle
      counter := 0;
      //Reset stopwatch to zero for next cycle
      sw.Reset;
      //Start stopwatch agina for next cycle
      sw.Start;
    end;
  //Stop the StopWatch since we no longer need it
  sw.Stop;
  //Free up the stopwatch record to free up the used memory
  sw.Free;
end;

计算运营率？例如。每秒检查X.

2 个答案: