TerraSlave and TerraDispatcher

Applies to TerraScan and TerraSlave v020.006 and later. A TerraSlave User Guide is available from Terrasolid. View a short tutorial on using TerraSlave and TerraDispatcher.

TerraSlave

  • Windows executable for batch processing TerraScan, TerraPhoto and TerraMatch tasks
  • Alternative method for running processes TerraScan/Photo/Match can run
  • Advantages:
    • Run batch processes without tying up CAD software
    • Run multiple instances on one computer to speed up task
    • Distribute processing to multiple computers to speed up task

Terminology

  • Master computer is a computer where human user initiates a task with TerraScan, TerraPhoto or TerraMatch.
  • Slave computer is a computer processing tasks initiated from some other computer. Slave computer can be a computer without a human operator. Master computer can act as a slave computer for tasks initiated from other computers.
  • Working segment is a set of data to be processed. Working segment can be for example:
    • one TerraScan project block
    • one TerraPhoto image
  • Distributed processing is computation involving multiple computers. One computer acts as master computer, other computers act as slave computers.
  • Single computer processing is computation taking place on computer only. It can run with multiple program instances running concurrently on the same computer.

Technical Requirements for Distributed Processing

  • 64-bit Windows operating system – Windows 10 or later
  • Launching computer must:
    • Have \terra64 folder shared for read access
    • Have data folder shared for read/write (source data, result data, macro)
    • Have read/write access to \terra64\tslave folder of participating computers
  • Participating computers must:
    • Have \terra64\tslave folder shared for read/write
    • Have read/write access to \terra64\tslave folder of launching computer
    • Have read/write access to data
  • Software will convert local paths such as “e:\jyvaskyla\laser01” to UNC paths such as “\\TYOASEMA\jyvaskyla\laser01” automatically
  • Use UNC paths yourself to verify that everything is properly shared

Note: For more complex dispatched and distributed processing, more user control, tracking and reporting please see the GeoCue Workflow Management System.

Software Components Involved

  • TerraScan / TerraPhoto / TerraMatch launches a task to be processed by TerraSlave
    • Run a macro on each project block
    • Compute feature points for every image
  • TerraDispatcher dispatches working segments to participating computers
    • For master computer: TerraDispatcher starts TerraSlave with a segment assigned
    • For slave computer: TerraDispatcher writes segment assignment as a file for TerraSlaveService
  • TerraSlaveService is a service running on a slave computer. It checks regularly for segment assignment files appearing in \terra64\queue. If found, it launches TerraSlave. TerraSlaveService has no user interface.
  • TerraSlave is an executable which processes one working segment at a time. TerraSlave.exe has no user interface.

TerraSlave Licensing

  • Separate TerraSlave license needs to be purchased for computers with no TerraScan/TerraPhoto/TerraMatch license
  • Computer with TerraScan license can run TerraScan tasks in TerraSlave
  • Computer with TerraPhoto license can run TerraPhoto tasks in TerraSlave
  • Computer with TerraMatch license can run TerraMatch tasks in TerraSlave

Computer Hardware Recommendations

  • TerraSlave has same hardware requirements as TerraScan: 32 GB RAM
    • 32GB enough for running 1-2 instances of TerraSlave with 100 million point block size
  • You can make good use of high core count processors with TerraSlave
    • Highly threaded task: one TerraSlave instance can use many cores
    • Single threaded task: you can dispatch many instances of TerraSlave
  • To run many instances of TerraSlave, you should have more RAM
    • Add 8 – 16 GB RAM for each additional instance when using 100 million point block size
  • For distributed processing: make sure computers have fast connection to the data

Master Computer Software Setup

  • Run normal TerraScan/TerraPhoto/TerraMatch setup
Terra Setup
  • This will install TerraDispatcher and TerraSlave as part of TerraScan setup
  • No need to separately install TerraSlave unless you want to use the same computer as a slave computer (=run tasks initiated from other computers)

Slave Computer Software Setup

  • Run TerraSlave setup on all computers which will act as a slave computer
  • This will install TerraSlave and TerraSlaveService
  • TerraSlaveService needs a user name and password for an account which will have appropriate read/write access to shared folders
TerraSlave Setup v020.006 and later

If the TerraSlaveService does not install as it should using setup.exe, manually install the service.

TerraSlave Folder Structure

  • TerraSlave relies on a fixed folder structure under installation folder (default c:\terra64)
New TSlave Folder Structure

Slave Computer List in TerraScan/Photo

  • User defines a list computers which participate in computation tasks
  • Default list is just the local computer
TerraScan-> Settings -> Slave Computers

TerraDispatcher User Interface

  • TerraDispatcher user interface lets you:
    • Pause or Resume automatic dispatching
    • Abort task
    • Move computers up or down in priority order
  • When automatic dispatching is paused, you can:
    • Remove working segments from the list
    • Reset working segments to pending status
    • Dispatch working segments to computer selected in lower list
TerraDispatcher

TerraSlave Preferences File

  • TerraSlave has no user interface
  • You can modify user preferences by editing c:\terra64\tslave\tslave.upf text file
VariableDescription
ApplicationTerraSlave – do not modify
LicDirLocation of license files
LicUseServerIf non zero, requests a license from license server*
LicServerLicense server computer name
LicAccessAccess code for license server
RunTasksHistorical – do not modify
MaxThreadsMax number of threads Value of 0 or -1 means all processor cores

*Note: TerraSlave license self-checkout is not currently working when tslave.exe exists in the tslave folder.

If you don’t have a tslave.upf from the old TerraSlave installation, copy the contents of the following to a text file, adjust to fit your needs, and save as tslave.upf in your %terra%\tslave folder.

[Terra preferences]
Application=TerraSlave
LicDir=C:\terra64\license\
LicUseServer=0
LicServer=
LicAccess=
RunTasks=2
MaxThreads=16

Task Manager Instructions

  • Use Task Manager to see how much processor power and how much memory is in use

Note: If the processor has hyperthreading on, Task Manager shows 50% processor usage when almost all power is in use

  • Never let memory usage reach 100%
  • Aim for about 50% processor usage for single threaded tasks
    • Single threaded tasks (ground, hard surface, height from ground) typically access memory non-linearly and hyperthreading gives no speed improvement
  • Aim for 50% – 100% processor usage for multithreaded tasks
    • Nicely multithreaded tasks (classify surface points, compute normal vectors) have a lot of linear memory access and hyperthreading speeds up the task

How Number of Instances Affects Execution Time

Execution time vs Number of Instances
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