eValid™ -- Automated Web Quality Solution Browser-Based, Client-Side, Functional Testing & Validation, Load & Performance Tuning, Page Timing, Website Analysis, and Rich Internet Application Monitoring. © Copyright 2000-2008 by Software Research, Inc.

Summary
When running LoadTest scenarios -- i.e. a loadtest.evl type playback script -- remember that you are asking eValid to launch each *.evs script in its own eValid browser. Because eValid imposes NO limit on the number of browsers you can open with eValid's LOAD LoadTest feature it is fairly easy to overload your system resources.

Typical Symptoms
Warning messages (in the form of modal popups) from the Windows operating system like "Failed to create empty document" or "An unsupported operation was attempted" are the usually result of an eValid LoadTest run that is overloading the operating system in some way.

Note the neither of these error messages is actually from eValid per se, but instead are eValid's response to requests made to the underlying operating system.

In most cases you can run up to ~20 parallel eValid instances without seeing either of these messages. With more than ~20 parallel eValid instances you will likely see these messages regularly.

Key Parameters
There are several key system settings: Virtual Memory, Desktop Heap, Performance Options, and Memory usage. These system settings may need to be adjusted to get the best performance out of eValid in LoadTest mode.

It is good practice to copy down and/or make backup files of your default system settings in case you need to re-establishing default settings.

Base Machine Description
The instructions to set Virtual Memory and Desktop Heap settings were made using the following PC:

The actual number you have to set Virtual Memory and/or Desktop Heap settings to may vary due to hardware, OS, and LoadTest configurations.

Machine Adjustments

1. How To Set Virtual Memory Size
   Applies to Windows 2000 Professional Edition, Windows XP and Windows Vista. Here is the sequence to set the Virtual Memory Size.

   For Windows 2000 Users:

   1. Right Click [My Computer]
   2. Select [Properties]
   3. Select[Advanced] > [Performance Options...] > [Change]
   4. Set Initial Size(MB): 900
   5. Maximum Size(MB): 900
   6. Click [Set] > [OK] and exit out completely.
   7. Reboot the machine to have changes take effect.

   For Windows XP Users:

   1. Right Click [My Computer]
   2. Select [Properties]
   3. Select[Advanced] > [Performance] > [Settings]
   4. Select[Advanced] > [Virtual Memory] > [Change]
   5. Set Initial Size(MB): 900
   6. Maximum Size(MB): 900
   7. Click [Set] > [OK] and exit out completely.
   8. Reboot the machine to have changes take effect.

   For Windows Vista Users:

   1. Right Click [My Computer]
   2. Select [Properties]
   3. Select[Advanced] > [Performance] > [Settings]
   4. Select[Advanced] > [Virtual Memory] > [Change]
   5. Click on [System managed size] to have Windows choose the best size of the paging file.
   6. Click [Set] > [OK] and exit out completely.
   7. Reboot the machine to have changes take effect.

2. How To Set Desktop Heap Size
   Here is the sequence of changes to be made to set the Desktop Heap Size.
   1. Select [Start Menu] > [Run] then type regedit and click [OK] button.
   2. In the registry editor select:

      [HKEY_LOCAL_MACHINE] > [System] > [CurrentControlSet] > [Control] > [SessionManager] > [SubSystems]

   3. Right click [Windows]
   4. In the pop up menu select [Modify].
   5. In the editable dialog-box copy and paste the long string into a text file using Notepad or some text editor to save the setting as a backup.
   6. In the editable dialog-box use the arrow key to scroll to the part of the string that reads:

      Machine OS	Original Registry Setting
      Windows 2000/XP	SharedSection=1024,3072,512
      Windows Vista	SharedSection=1024,12288,512

   7. Change the "3072" or "12288" to "16384" for 25+ parallel playbacks or set change the "3072" or "12288" to "32768" for up to 50+ parallel playbacks.

   ADDITIONAL NOTES:

   • The above was found by searching for "Heap Settings" and "Desktop Heap Settings" at www.microsoft.com, where more recent information may be available.
   • The three numbers above, "1024,3072,512" or "1024,12288,512" may vary from machine to machine. Be sure to change only the second value ("3072") or ("12288"), or whatever number is in its place, to the numbers mentioned above, or adjust the number that favors your machine and LoadTest needs.
   • You have to have enough system memory (RAM) to satisfy the requirements of the previous setting(s).
   • You will have to try different settings using the above methods as each machine, hardware, and OS, may be slightly different in its requirements.

3. Changing the Performance Options
   Changing the performance options of Windows 2000 Professional can adequately assist in allocating enough resources to aid in completion of LoadTests with large numbers of browser to be opened.

   To change the Performance Options in Windows 2000:

   1. Right click [My Computer]
   2. Click on [Properties]
   3. Click on [Advanced]
   4. Click on [Performance Options]
   5. Click on [Optimize Performance for Background Services]
   6. Click on [OK] and exit out completely.
   7. Reboot the machine to have these changes take effect.

   To change the Performance Options in Windows XP:

   1. Right click [My Computer]
   2. Click on [Properties]
   3. Click on [Advanced]
   4. Click on [Performance] > [Settings]
   5. Click on [Advanced] in Performance Options
   6. Click on [Processor Scheduling for Background Services]
   7. Click on [Memory Usage for System Cache]
   8. Click on [OK] and exit out completely.
   9. Reboot the machine to have these changes take effect.

   To change the Performance Options in Windows Vista:

   1. Right click [My Computer]
   2. Click on [Properties]
   3. Click on [Advanced]
   4. Click on [Performance] > [Settings]
   5. Click on [Advanced] in Performance Options
   6. Click on [Processor Scheduling for Background Services]
   7. Click on [OK] and exit out completely.
   8. Reboot the machine to have these changes take effect.

4. Video Card Issues
   LoadTest runs often are graphics-intensive processes. There are known video card issues in such runs. Tests which exceed more than a large number simultaneous playbacks may affect the refresh rate of the screen and this may make the screen unreadable.

   eValid V6 build #172 and later used a different method for handling allocation of Global Data Objects, and the incidence of video card interaction failures are considerably reduced.

   To ensure smooth operation of 50+ simultaneous eValid browsers, we recommend having at least 64 MB of RAM allocated for the video. To check the amount of RAM your video card has installed:

   For Windows 2000 Users:

   1. Click on [Start]
   2. Click on [Settings]
   3. Click on [Control Panel]
   4. Click on [Display]
   5. Click on [Settings]
   6. Click on [Advanced]
   7. Click on the [Display Type]
   8. Click on the [Adapter] tab

   The amount of RAM present with your video card should be indicated here by Memory Size.

   For Windows XP Users:

   1. Click on [Start]
   2. Click on [Control Panel]
   3. Click on [Display]
   4. Click on [Settings]
   5. Click on [Advanced]
   6. Click on the [Adapter] tab

   For Windows Vista Users:

   1. Click on [Start]
   2. Click on [Control Panel]
   3. Click on [Display]
   4. Click on [Settings]
   5. Click on [Advanced]
   6. Click on the [Adapter] tab

   The amount of RAM present with your video card should be indicated here by Memory Size.

IE Connection Limit
Although this would be very rare, here is the Microsoft KB article on How To Configure Internet Explorer to Have More Than Two Download Sessions.