This setting controls the threshold at which tasks are considered to be eligible for execution by fast lane threads.
All tasks with an expected execution time below this setting can be executed by fast lane threads.
Increasing the value of this setting will expand the ability of fast lane threads to execute more tasks held within the processing queue. This can result in overall higher engine throughput as more execution threads will be able to process the (usually slower) tail of the pipeline.
A higher setting can inhibit the responsiveness of the engine, as this increases the probability that all available threads become tied up with long running tests and are unable to provide timely response to changes being made to the codebase.