Which libs to use ?

[aidave]

Whats a good alternative to Timer?

[JSoftware]

QueryPerformanceCounter :mrgreen:

[Robert Kosek]

QueryPerformanceCounter :mrgreen:

Written for Delphi, but easy to adapt to FPC. My "Quick Timers" unit:

(******************************************************************************
 *  The contents of this file are subject to the Mozilla Public License       *
 *  Version 1.1 (the "License"); you may not use this file except in          *
 *  compliance with the License. You may obtain a copy of the License at      *
 *  http://www.mozilla.org/MPL/                                               *
 *                                                                            *
 *  Software distributed under the License is distributed on an "AS IS"       *
 *  basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See the   *
 *  License for the specific language governing rights and limitations        *
 *  under the License.                                                        *
 *                                                                            *
 *  The Original Code is uQTimers.pas.                                        *
 *                                                                            *
 *  The Initial Developer of the Original Code is Robert "The Wicked Flea"    *
 *  Kosek. Portions created by Robert Kosek are Copyright (C) May 2006.       *
 *  All Rights Reserved.                                                      *
 ******************************************************************************)
unit uQTimers;

interface

uses Windows;

type
  TQuickTimer = record
    Start, Stop: Int64;
  end;

{ Returns a number for the running timer.                                      }
function StartTimer: Integer;
{ When given a number the timer will be removed and the result will be
  the seconds elapsed.                                                         }
function StopTimer(which: Integer): Extended;

var ProcessorSpeed: Int64;
    QTimers: array of TQuickTimer;

implementation

function StartTimer: Integer;
begin
  Result := length(QTimers);
  SetLength(QTimers,length(QTimers)+1);
  QueryPerformanceCounter(QTimers[Result].Start);
end;

function StopTimer(which: Integer): Extended;
  procedure RemoveIndex(Index: Integer);
  var i: integer;
  begin
    for i := Index to Length(QTimers)-1 do
      QTimers[i] := QTimers[i+1];
      
    SetLength(QTimers,Length(QTimers)-1);
  end;
begin
  QueryPerformanceCounter(QTimers[which].Stop);
  Result := (QTimers[which].Stop - QTimers[which].Start) / ProcessorSpeed;

  if which = length(QTimers) then
    SetLength(QTimers,length(QTimers)-1)
  else
    RemoveIndex(which);
end;

procedure KillTimers;
begin
  SetLength(QTimers,0);
end;

initialization
  QueryPerformanceFrequency(ProcessorSpeed);
finalization
  KillTimers;
end.

[JSoftware]

Robert, your unit seems usable but it has some serious bugs. Take for instance:

i := starttimer;
i2 := starttimer;
stoptimer(i);
stoptimer(i2);

this would make the procedure try to access the value in QTimers[i2] which would be QTimers[1]. This array entry does however not exist due to that we set the length of the array to 1 when we stopped timer i.

[WILL]

Robert: Well thats one way to distribute your code. :lol:

[Chebmaster]

QueryPerformanceCounter(

AFAIK, there is no such function in unix :?

[Robert Kosek]

Robert, your unit seems usable but it has some serious bugs. Take for instance:

i := starttimer;
i2 := starttimer;
stoptimer(i);
stoptimer(i2);

this would make the procedure try to access the value in QTimers[i2] which would be QTimers[1]. This array entry does however not exist due to that we set the length of the array to 1 when we stopped timer i.

It's not a bug, it's the design purpose that I had in mind. Such as nested timers. The simple way to fix that would be to implement a timer_kill function so that you could deallocate the entry when it's not in use. The use I happened to design it for would be:

i := StartTimer;
  i2 := StartTimer;
  StopTimer(i2);
StopTimer(i);

This way you could have a timer within a loop, and one without. So you could easily find both the mean and total time, mean of execution and the total time the loop took to execute.

WILL: LOL, Yup. I figured I'd help someone who is looking for snippets.

[JSoftware]

QueryPerformanceCounter(

AFAIK, there is no such function in unix :?

How about using rdtsc instead? Doesn't that work in unix?

[Chebmaster]

It should, but... The asm potentially limits the code portability, by tying it to Intel-32 bit platforms. Not that it matters too much, though.

But i heard, using RDTSC on a multi-processor system can royally screw things up.

[JSoftware]

But i heard, using RDTSC on a multi-processor system can royally screw things up.

I think sly or Will or someone else on this forum presented a way to get around that problem some time ago