Tasks that have the parallel processing factor  property in their context  parameter allow you to control the number of Raster Processing service instances that can be used for processing your data.
If the task's context parameter doesn't have the processor type  or if the processor type  in the task's context  is set as CPU, the parallel  controls Raster Processing (CPU) service instances. If the processor type  is set as GPU, the parallel processing factor  controls the number of Raster Processing GPU instances.
If the parallel processing factor  is not specified, which is the default, one Raster Analysis task will use 80 percent of the maximum number of Raster Processing service instances. Distributed Orthomapping task’s default is 50 percent.
By setting the parallel processing factor , you can request the number of parallel workers that the Raster Analytics Image Server should use to process one Raster Analytic task. However, if the total number of parallel processes exceeds the maximum number of Raster Processing service instances, the additional parallel processes will be queued.
Syntax example with a specified number of processing instances:
"parallelProcessingFactor": "2"Syntax example with a specified percentage of total processing instances:
"parallelProcessingFactor": "60%"