Description: Precision timer/stopwatch component for Lazarus/FPC Author: Tom Lisjac <netdxr@gmail.com> Contributors: Please see the Git repository commit history License: Modifyed LGPL (The same as Free Pascal RTL and LCL) Copyright (C) 2003-2006 by Tom Lisjac Latest version can be obtained at: http://wiki.lazarus.freepascal.org/EpikTimer Contents: 1. The EpikTimer.pas component and palette icon 2. ETPackage.lpk package for installation 3. ETDemo demonstration app and host system clock evaluator ----------------------------------------------------------------- The EpikTimer Component Documentation: See epiktimer.pas for detailed discussion of timebase sources, timing accuracy and clock correlation techniques that can provide traceable precision during long term measurements. Installation: - In Components/Open Package File, open etpackage.lpk. - Compile the component to verify that everything is there. - Install and let Lazarus rebuild - Component will be in the System Palette (stopwatch-ruler icon) Usage: Drop the component on a form. The component contains a single timer instance and parameterless calls to start, stop, elapsed and clear will implicitly reference it. If the timer is named ET: Procedure InstrumentedCall; Begin ET.Clear; // optional... timer is cleared at creation ET.Start; ExecuteFirstTimedSection; ET.Stop; // the timer is actually paused and can be restarted later TimedSection1:=ET.Elapsed; // store the elapsed in a global MakeAnUntimedOverheadCall; // not counted in the timer ET.Start; //resume the timer... continue accumulating ticks CallTimedSection2; TimedSection2:=ET.Elapsed; //timer keeps running... we've just sample it. CallTimedSection3; CallSomethingElse; TimedSection3:=ET.Elapsed; //keep counting... tap the elapsed CallTimedSection4; TimedSection4:=ET.Elapsed; //keep counting... tap the elapsed ET.clear // done... timer is stopped and zeroed end; You can also create any number of timers from a single component on the form by declaring a TimerData record and passing it as a parameter to start, stop, elapsed and clear using the overloaded methods in the component. An example would be: Function TimedExecution:Extended; Var DiskAccessTime:TimerData; Begin ET.Clear(DiskAccessTimer); // Declared timers *must* be cleared before use. ET.Start(DiskAccessTimer); ExecuteTheTimedSection; Result:=ET.Elapsed(DiskAccessTimer); // the timer keeps running... etc... See etdemo.pas for additional examples of component usage The ETDemo Application The ETDemo application does not require EpikTimer to be installed in order to compile and operate. I never liked having to install a palette full of components only to find out that I didn't like any of them! :) Installation Open etdemo.lpi and compile it. Operation As the program comes up, it will create and initialize 10 invisible timer forms that can be spawned from the main program's Stopwatch group box. A progress bar is supposed to reduce the boredom. Host Hardware Information This group evaluates the host system and reports if it finds hardware support for the Pentium Time Stamp Counter. If so, you'll be able to get a snapshot of it's value along with the microsecond ticks from your OS clock. The sizes of the hardware and system ticks isn't as important as the rates that they change. On a Linux system, the system ticks value represent microseconds of Epoch time. Timebase Calibration If your system lacks the TSC or a microsecond resolution system clock, EpikTimer falls back to using gated measurements for setting the internal tick frequencies. Timing is non-deterministic when calling the Linux kernel so some averaging and smoothing of the resulting jitter is helpful. If EpikTimer is in this mode, long term accuracy isn't guaranteed... but short term comparitive measurements can still be made. Pressing "Calibrate" performs overhead extraction and gates the selected timebase against the best timebase gate available on a given host. The results are displayed in the memo boxes. Timebase Correlation This is the default mode for measuring the TSC frequency and provides a reliable mechanism for synchronizing the TSC ticks to the system clock. If the system clock is maintained via NTP and the CorrelateTimebases method is called at regular intervals, the TSC stream can display the same long term accuracy (at very high resolutions) as the quality of the system's synchronizing time source. Timer/Stopwatch Functions This section implements a single stopwatch using the component's internal timer data record. The Spawn Timers group box will bring up the 10 timers that were created and initialized during program startup. ----------------- End of EpikTimer Release Documentation ------------------