Have you ever had the feeling that window updates and menu pull-downs are just a bit slower after installing this new gadget, or after turning virtual memory on? Now you can quantify this feeling about the responsiveness of your computer. When you play this game or play that QuickTime movie, have you experienced some jerkiness? While some of that jerkiness is due to hardware (especially CD-ROMs), some of it might be alleviated by removing some control panels and extensions. But which ones make a difference?
Every time applications surrender control of the CPU, the system goes through a number of internal processes and executes some code patched on the system from extensions and control panels. Since this code is executed at every event loop, applications that are multitasking friendly are penalized in speed. The overhead on the event loop resulting from the extension and control panel code is measured by the average response time. In addition, this overhead is not constant each time through the event loop. This can make the applications "jerk". Now, you can measure your computer's jerkiness.
This is emailware. It's free, but you must send me an email:
pmeunier@purdue.edu
How to use it:
Start the application. Quit all other applications, unless you want to test the effect of having a given application in the background. Under the menu "Measure", select "Response Time" or "Jerkiness". The menu will stay selected until the end of the test (no, the computer hasn't crashed! Actually, you can even bring another application to the front, but that will affect the results.). Do not do anything during the test, unless you want to see the effect of some specific action. The text window will log the results of the tests. To see the greatest possible performance of your computer, start up your computer with all extensions off or with only Speed Emulator (Speed Emulator is part of the "Speed Doubler" product from Connectix for PowerPC computers), and redo the tests.
Benchmarks: a PowerCenter Pro 180 completes the 2000 loops on average in about 20 ticks, or less than 0.17 milliseconds/loop (with the 68K version of this program; the PowerPC native version actually takes longer, possibly because some MacOS 8 code is still 68K and has to be emulated). My 6100/66 takes about 1 millisecond/loop on average.
Some of the code used in this application is based on TESample by Apple Computer. I fixed the horizontal scroll bar bug in the version that was distributed with Code Warrior 9. This application was compiled using Code Warrior Academic Pro v.9, so it's free. Thanks to MetroWerks for making an academic version available at discount pricing, and for sending me updates since Code Warrior version 6 up to version 9. When I'll have more money and feel the need enough I'll subscribe for more updates.
copyright Pascal Meunier, August 1997, all rights reserved.
