Queue Keeps Growing

During a traffic surge a service is CPU saturated. Its work queue has grown to 40 seconds of backlog, p99 latency is 12 seconds, and callers time out at 2 seconds. Throughput of useful responses has collapsed to near zero. What is the right intervention?

A

Retry timed out requests server side so the work already sitting in the queue eventually produces a response the caller accepts on the second attempt

B

Apply admission control at the front door: reject arrivals immediately once queue wait exceeds the caller deadline, and drop queued items already past it

C

Increase the queue capacity so the surge is buffered rather than rejected, and let the backlog drain once the arrival rate falls under the service rate

D

Raise the worker thread count so that more requests run concurrently, giving the saturated CPUs more work in flight to interleave between blocking calls and stalls