Question 70
A team says it corrected this issue: The operator sees repeated training slowdowns after a rack cooling change but assumes the NCCL library is defective. What evidence best confirms that it is fixed?
Explanation
Correct Answer
A completed remediation must demonstrate that After cooling remediation, GPU clock limits normalize and iteration times recover. That tests the specific weakness because Thermal throttling can reduce compute progress and create collective stragglers without an NCCL defect.
Incorrect Answers
This is weaker evidence because Thermal throttling can reduce compute progress and create collective stragglers without an NCCL defect. The independent test must show that After cooling remediation, GPU clock limits normalize and iteration times recover.
This alternative addresses the separate case “A multi-GPU server repeatedly loses one NIC link when its fan tray slows under load”. A completed remediation must demonstrate that After fan repair, full-load NIC and GPU tests run with stable temperatures and no link flaps. The deciding requirement here is “After cooling remediation, GPU clock limits normalize and iteration times recover”.
The option would apply to “A training node reports intermittent GPU Xid faults during collective operations but its nvidia-smi inventory remains normal”. The strongest acceptance result is that A controlled reproduction isolates the failing accelerator and repeated validation runs stop producing the Xid events, not merely that a command executed. This question instead requires “After cooling remediation, GPU clock limits normalize and iteration times recover”.