Number of Instances
TerraBatch uses one instance for processing one working segment. The use of multiple instances enables the parallel processing of several working segments on one computer. The number of instances used for TerraBatch processing may effect the processing speed and overall performance of a computer. There is no single value recommendation for how many instances should be used as it depends on many different factors, such as processor cores, hyperthreading, RAM and processing steps that are part of a task.
The user can set the maximum number of instances on different places in the software:
•in the Batch computers category of TerraScan Settings
•in the TerraBatch Task Settings dialog of the Macro window of TerraScan
•in TerraDispatcher while a task is running
On the master computer, you can verify the suitability of the settings with the help of the Windows Task Manager. Start the Task Manager while a task, such as a macro is running on the computer. Check the CPU and RAM usage against the following recommendations:
•RAM usage should never reach 100%.
•CPU usage should be about 50% for single-threaded tasks. Single-threaded tasks access the memory in a non-linear way and hyperthreading does not provide any speed improvement. Examples for single-threaded processing tasks in TerraScan are the ground classification, hard surface classification, by height from ground computation and classification, and others.
•CPU usage should be about 50-100% for multi-threaded tasks. Multi-threaded tasks access memory in a linear way and hyperthreading speeds up processing. Examples for multi-threaded processing tasks in TerraScan are surface classification, normal vector computation, and others.
If the CPU/RAM usage on your master computer is not optimal, modify the number of instances in TerraDispatcher. The Task Manager will show the effect.
The use of more than 4 instances may not lead to a significant speed improvement anymore. A test with two different processor types showed that a value > 4 instances increases the processing speed only at a very low level. For a 14-core processor, the optimal number was 8 instances, while for a 32-core processor, the optimal number was 12 instances.
