Resource Class Allocation and Parallelism Concurrency Limits

CircleCI allows the definition of resource_class to manage CPU and RAM allocations, while the parallelism parameter splits jobs across multiple concurrent containers to reduce execution time.

When scaling a pipeline, there is a need to balance high parallelism with organization-level concurrency limits to ensure that resource-intensive jobs do not saturate available runner capacity or exhaust credits prematurely.

It is unclear how the orchestrator prioritizes resource allocation when multiple pipelines with high parallelism settings compete for the same limited concurrency slots.

• Does the concurrency limit apply to the total number of parallel containers or the number of parent jobs?
• How does the system handle resource class requests when the organization-wide concurrency cap is reached?