NVIDIA NCP-AII Practice Test 76
Question 750
During an NVIDIA AI factory acceptance test, engineers discover: The team invokes nccl-tests on one GPU and claims all internal NVLink paths have been validated. Which TWO complementary elements are needed: the correct technical action and the strongest independent diagnostic evidence? Select TWO answers.
- Inspect nccl-tests output verification flags, message sizes, GPU logs and reproducible error traces.
- Consider a single-GPU CUDA sample sufficient to certify an eight-GPU NVSwitch collective network.
- Run supported single-node NCCL collectives spanning the intended local GPUs and compare with baseline topology.
- Inspect local device topology, nccl-tests rank count, all-reduce bandwidth and link error metrics.
- Validate the complete rank count, GPU mapping and launch environment on all participating nodes.
Explanation
Correct Answers
C:This is an appropriate correction for Intra-node NCCL all-reduce test scope: Run supported single-node NCCL collectives spanning the intended local GPUs and compare with baseline topology. Observed scenario: The team invokes nccl-tests on one GPU and claims all internal NVLink paths have been validated. The governing mechanism is: NCCL collective execution stresses GPU peer paths and coordination beyond the capabilities of independent CUDA kernels.
D:This is the direct operational evidence to investigate: Inspect local device topology, nccl-tests rank count, all-reduce bandwidth and link error metrics. Observed scenario: The team invokes nccl-tests on one GPU and claims all internal NVLink paths have been validated.
Incorrect Answers
A:This alternative is relevant to NCCL device buffers and data integrity checks but does not directly resolve the current Intra-node NCCL all-reduce test scope issue: Inspect nccl-tests output verification flags, message sizes, GPU logs and reproducible error traces. Observed scenario: The team invokes nccl-tests on one GPU and claims all internal NVLink paths have been validated.
B:This tempting but unsafe shortcut is not a sufficient remediation for Intra-node NCCL all-reduce test scope: Consider a single-GPU CUDA sample sufficient to certify an eight-GPU NVSwitch collective network. The team invokes nccl-tests on one GPU and claims all internal NVLink paths have been validated. NCCL collective execution stresses GPU peer paths and coordination beyond the capabilities of independent CUDA kernels.
E:This alternative is relevant to NCCL communicator and rank-to-device consistency but does not directly resolve the current Intra-node NCCL all-reduce test scope issue: Validate the complete rank count, GPU mapping and launch environment on all participating nodes. Observed scenario: The team invokes nccl-tests on one GPU and claims all internal NVLink paths have been validated.
Question 751
A production GPU cluster review identifies this condition: The team invokes nccl-tests on one GPU and claims all internal NVLink paths have been validated. Which diagnostic evidence should be obtained FIRST to substantiate the likely fault or configuration gap? Select ONE best answer.
- Inspect dcgmi diag suite results, entity IDs, error logs, driver state and conflicting running workloads.
- Inspect local device topology, nccl-tests rank count, all-reduce bandwidth and link error metrics.
- Consider a single-GPU CUDA sample sufficient to certify an eight-GPU NVSwitch collective network.
- Inspect RDMA device state, NCCL transport logs, port counters, rank mapping and cross-node bandwidth.
Explanation
Correct Answer
B:This is the direct operational evidence to investigate: Inspect local device topology, nccl-tests rank count, all-reduce bandwidth and link error metrics. Observed scenario: The team invokes nccl-tests on one GPU and claims all internal NVLink paths have been validated. The governing mechanism is: NCCL collective execution stresses GPU peer paths and coordination beyond the capabilities of independent CUDA kernels.
Incorrect Answers
A:This alternative is relevant to DCGM active single-node diagnostic suites but does not directly resolve the current Intra-node NCCL all-reduce test scope issue: Inspect dcgmi diag suite results, entity IDs, error logs, driver state and conflicting running workloads. Observed scenario: The team invokes nccl-tests on one GPU and claims all internal NVLink paths have been validated.
C:This tempting but unsafe shortcut is not a sufficient remediation for Intra-node NCCL all-reduce test scope: Consider a single-GPU CUDA sample sufficient to certify an eight-GPU NVSwitch collective network. Observed scenario: The team invokes nccl-tests on one GPU and claims all internal NVLink paths have been validated. The governing mechanism is: NCCL collective execution stresses GPU peer paths and coordination beyond the capabilities of independent CUDA kernels. The proportionate action is: Run supported single-node NCCL collectives spanning the intended local GPUs and compare with baseline topology.
D:This alternative is relevant to Inter-node NCCL east-west RDMA readiness but does not directly resolve the current Intra-node NCCL all-reduce test scope issue: Inspect RDMA device state, NCCL transport logs, port counters, rank mapping and cross-node bandwidth. Observed scenario: The team invokes nccl-tests on one GPU and claims all internal NVLink paths have been validated.
Question 752
In a professional AI infrastructure deployment, a technician observes: The team invokes nccl-tests on one GPU and claims all internal NVLink paths have been validated. After corrective work, which observable result BEST confirms that the requirement is met? Select ONE best answer.
- Observed performance meets both small-message latency and large-message throughput objectives for intended jobs.
- Consider a single-GPU CUDA sample sufficient to certify an eight-GPU NVSwitch collective network.
- All planned ranks join the intended communicator and finish the same collective without duplicate device placement.
- All intended GPUs participate in successful collectives with expected local throughput and no fabric faults.
Explanation
Correct Answer
D:This is an observable verified result, not merely a claimed configuration change: All intended GPUs participate in successful collectives with expected local throughput and no fabric faults. Observed scenario: The team invokes nccl-tests on one GPU and claims all internal NVLink paths have been validated.
Incorrect Answers
A:This alternative is relevant to NCCL bandwidth and latency payload sweep but does not directly resolve the current Intra-node NCCL all-reduce test scope issue: Observed performance meets both small-message latency and large-message throughput objectives for intended jobs. Observed scenario: The team invokes nccl-tests on one GPU and claims all internal NVLink paths have been validated.
B:This tempting but unsafe shortcut is not a sufficient remediation for Intra-node NCCL all-reduce test scope: Consider a single-GPU CUDA sample sufficient to certify an eight-GPU NVSwitch collective network. Observed scenario: The team invokes nccl-tests on one GPU and claims all internal NVLink paths have been validated. The governing mechanism is: NCCL collective execution stresses GPU peer paths and coordination beyond the capabilities of independent CUDA kernels. The proportionate action is: Run supported single-node NCCL collectives spanning the intended local GPUs and compare with baseline topology. A direct check is: Inspect local device topology, nccl-tests rank count, all-reduce bandwidth and link error metrics. The acceptance condition is: All intended GPUs participate in successful collectives with expected local throughput and no fabric faults.
C:This alternative is relevant to NCCL communicator and rank-to-device consistency but does not directly resolve the current Intra-node NCCL all-reduce test scope issue: All planned ranks join the intended communicator and finish the same collective without duplicate device placement. Observed scenario: The team invokes nccl-tests on one GPU and claims all internal NVLink paths have been validated.
Question 753
The cluster operations team needs to evaluate this situation: A maintenance replacement changes NVSwitch connectivity but no collective communication test follows. Which operational response is MOST appropriate to address the root issue? Select ONE best answer.
- Benchmark supported collective strategies and rank mappings against actual topology and message sizes.
- Consider a single-GPU CUDA sample sufficient to certify an eight-GPU NVSwitch collective network.
- Validate intended inter-node RDMA devices, transport selection and network reachability with multi-node NCCL tests.
- Run supported single-node NCCL collectives spanning the intended local GPUs and compare with baseline topology.
Explanation
Correct Answer
D:This is an appropriate correction for Intra-node NCCL all-reduce test scope: Run supported single-node NCCL collectives spanning the intended local GPUs and compare with baseline topology. Observed scenario: A maintenance replacement changes NVSwitch connectivity but no collective communication test follows.
Incorrect Answers
A:This alternative is relevant to NCCL algorithm choice and topology mapping but does not directly resolve the current Intra-node NCCL all-reduce test scope issue: Benchmark supported collective strategies and rank mappings against actual topology and message sizes. Observed scenario: A maintenance replacement changes NVSwitch connectivity but no collective communication test follows.
B:This tempting but unsafe shortcut is not a sufficient remediation for Intra-node NCCL all-reduce test scope: Consider a single-GPU CUDA sample sufficient to certify an eight-GPU NVSwitch collective network. A maintenance replacement changes NVSwitch connectivity but no collective communication test follows.
C:This alternative is relevant to Inter-node NCCL east-west RDMA readiness but does not directly resolve the current Intra-node NCCL all-reduce test scope issue: Validate intended inter-node RDMA devices, transport selection and network reachability with multi-node NCCL tests. Observed scenario: A maintenance replacement changes NVSwitch connectivity but no collective communication test follows.
Question 754
At a multi-node AI infrastructure handoff, the team records: A maintenance replacement changes NVSwitch connectivity but no collective communication test follows. Which underlying infrastructure principle BEST explains the issue? Select ONE best answer.
- Consider a single-GPU CUDA sample sufficient to certify an eight-GPU NVSwitch collective network.
- Collective scheduling and transport are sensitive to communicator geometry and payload sizes; one algorithm is not universally optimal.
- NCCL collective execution stresses GPU peer paths and coordination beyond the capabilities of independent CUDA kernels.
- Collectives require coordinated communicator membership and consistent rank participation; partial launches can hang.
Explanation
Correct Answer
C:This is the governing infrastructure principle: NCCL collective execution stresses GPU peer paths and coordination beyond the capabilities of independent CUDA kernels. Observed scenario: A maintenance replacement changes NVSwitch connectivity but no collective communication test follows.
Incorrect Answers
A:This tempting but unsafe shortcut is not a sufficient remediation for Intra-node NCCL all-reduce test scope: Consider a single-GPU CUDA sample sufficient to certify an eight-GPU NVSwitch collective network. A maintenance replacement changes NVSwitch connectivity but no collective communication test follows. NCCL collective execution stresses GPU peer paths and coordination beyond the capabilities of independent CUDA kernels.
B:This alternative is relevant to NCCL algorithm choice and topology mapping but does not directly resolve the current Intra-node NCCL all-reduce test scope issue: Collective scheduling and transport are sensitive to communicator geometry and payload sizes; one algorithm is not universally optimal. Observed scenario: A maintenance replacement changes NVSwitch connectivity but no collective communication test follows.
D:That option concerns NCCL communicator and rank-to-device consistency. The proportionate action is: Run supported single-node NCCL collectives spanning the intended local GPUs and compare with baseline topology.
Question 755
During an NVIDIA AI factory acceptance test, engineers discover: A maintenance replacement changes NVSwitch connectivity but no collective communication test follows. Which diagnostic evidence should be obtained FIRST to substantiate the likely fault or configuration gap? Select ONE best answer.
- Inspect nccl-tests output verification flags, message sizes, GPU logs and reproducible error traces.
- Consider a single-GPU CUDA sample sufficient to certify an eight-GPU NVSwitch collective network.
- Inspect dcgmi diag suite results, entity IDs, error logs, driver state and conflicting running workloads.
- Inspect local device topology, nccl-tests rank count, all-reduce bandwidth and link error metrics.
Explanation
Correct Answer
D:This is the direct operational evidence to investigate: Inspect local device topology, nccl-tests rank count, all-reduce bandwidth and link error metrics. Observed scenario: A maintenance replacement changes NVSwitch connectivity but no collective communication test follows.
Incorrect Answers
A:This alternative is relevant to NCCL device buffers and data integrity checks but does not directly resolve the current Intra-node NCCL all-reduce test scope issue: Inspect nccl-tests output verification flags, message sizes, GPU logs and reproducible error traces. Observed scenario: A maintenance replacement changes NVSwitch connectivity but no collective communication test follows.
B:This tempting but unsafe shortcut is not a sufficient remediation for Intra-node NCCL all-reduce test scope: Consider a single-GPU CUDA sample sufficient to certify an eight-GPU NVSwitch collective network. Observed scenario: A maintenance replacement changes NVSwitch connectivity but no collective communication test follows. The governing mechanism is: NCCL collective execution stresses GPU peer paths and coordination beyond the capabilities of independent CUDA kernels. The proportionate action is: Run supported single-node NCCL collectives spanning the intended local GPUs and compare with baseline topology.
C:This alternative is relevant to DCGM active single-node diagnostic suites but does not directly resolve the current Intra-node NCCL all-reduce test scope issue: Inspect dcgmi diag suite results, entity IDs, error logs, driver state and conflicting running workloads. Observed scenario: A maintenance replacement changes NVSwitch connectivity but no collective communication test follows.
Question 756
A production GPU cluster review identifies this condition: A maintenance replacement changes NVSwitch connectivity but no collective communication test follows. After corrective work, which observable result BEST confirms that the requirement is met? Select ONE best answer.
- All intended GPUs participate in successful collectives with expected local throughput and no fabric faults.
- The node sustains approved workload performance without unplanned throttling, errors or facility alarms.
- Consider a single-GPU CUDA sample sufficient to certify an eight-GPU NVSwitch collective network.
- All planned ranks join the intended communicator and finish the same collective without duplicate device placement.
Explanation
Correct Answer
A:This is an observable verified result, not merely a claimed configuration change: All intended GPUs participate in successful collectives with expected local throughput and no fabric faults. Observed scenario: A maintenance replacement changes NVSwitch connectivity but no collective communication test follows.
Incorrect Answers
B:This alternative is relevant to GPU thermal power and memory single-node burn-in but does not directly resolve the current Intra-node NCCL all-reduce test scope issue: The node sustains approved workload performance without unplanned throttling, errors or facility alarms. Observed scenario: A maintenance replacement changes NVSwitch connectivity but no collective communication test follows.
C:This tempting but unsafe shortcut is not a sufficient remediation for Intra-node NCCL all-reduce test scope: Consider a single-GPU CUDA sample sufficient to certify an eight-GPU NVSwitch collective network. Observed scenario: A maintenance replacement changes NVSwitch connectivity but no collective communication test follows. The governing mechanism is: NCCL collective execution stresses GPU peer paths and coordination beyond the capabilities of independent CUDA kernels. The proportionate action is: Run supported single-node NCCL collectives spanning the intended local GPUs and compare with baseline topology. A direct check is: Inspect local device topology, nccl-tests rank count, all-reduce bandwidth and link error metrics. The acceptance condition is: All intended GPUs participate in successful collectives with expected local throughput and no fabric faults.
D:This alternative is relevant to NCCL communicator and rank-to-device consistency but does not directly resolve the current Intra-node NCCL all-reduce test scope issue: All planned ranks join the intended communicator and finish the same collective without duplicate device placement. Observed scenario: A maintenance replacement changes NVSwitch connectivity but no collective communication test follows.
Question 757
In a professional AI infrastructure deployment, a technician observes: A communication test reports high transfer speed but distributed results differ across ranks due to data corruption. Which operational response is MOST appropriate to address the root issue? Select ONE best answer.
- Validate the complete rank count, GPU mapping and launch environment on all participating nodes.
- Validate collective correctness over representative sizes and iteration counts alongside throughput.
- Test NCCL throughput and latency across representative message sizes and node counts with repeatable conditions.
- Publish NCCL throughput numbers despite reported data-validation errors or hanging communicator ranks.
Explanation
Correct Answer
B:This is an appropriate correction for NCCL device buffers and data integrity checks: Validate collective correctness over representative sizes and iteration counts alongside throughput. Observed scenario: A communication test reports high transfer speed but distributed results differ across ranks due to data corruption.
Incorrect Answers
A:That option concerns NCCL communicator and rank-to-device consistency. Collective performance is not useful when data integrity or communicator completion fails.
C:This alternative is relevant to NCCL bandwidth and latency payload sweep but does not directly resolve the current NCCL device buffers and data integrity checks issue: Test NCCL throughput and latency across representative message sizes and node counts with repeatable conditions. Observed scenario: A communication test reports high transfer speed but distributed results differ across ranks due to data corruption.
D:This tempting but unsafe shortcut is not a sufficient remediation for NCCL device buffers and data integrity checks: Publish NCCL throughput numbers despite reported data-validation errors or hanging communicator ranks.
Question 758
The cluster operations team needs to evaluate this situation: A communication test reports high transfer speed but distributed results differ across ranks due to data corruption. Which underlying infrastructure principle BEST explains the issue? Select ONE best answer.
- Collective performance is not useful when data integrity or communicator completion fails.
- Collectives require coordinated communicator membership and consistent rank participation; partial launches can hang.
- Publish NCCL throughput numbers despite reported data-validation errors or hanging communicator ranks.
- Storage redundancy must preserve usable service and data consistency during faults, not merely expose two connections.
Explanation
Correct Answer
A:This is the governing infrastructure principle: Collective performance is not useful when data integrity or communicator completion fails. Observed scenario: A communication test reports high transfer speed but distributed results differ across ranks due to data corruption.
Incorrect Answers
B:This alternative is relevant to NCCL communicator and rank-to-device consistency but does not directly resolve the current NCCL device buffers and data integrity checks issue: Collectives require coordinated communicator membership and consistent rank participation; partial launches can hang. Observed scenario: A communication test reports high transfer speed but distributed results differ across ranks due to data corruption.
C:This tempting but unsafe shortcut is not a sufficient remediation for NCCL device buffers and data integrity checks: Publish NCCL throughput numbers despite reported data-validation errors or hanging communicator ranks. Collective performance is not useful when data integrity or communicator completion fails.
D:That option concerns Storage redundancy failover and data consistency. The proportionate action is: Validate collective correctness over representative sizes and iteration counts alongside throughput.
Question 759
At a multi-node AI infrastructure handoff, the team records: A communication test reports high transfer speed but distributed results differ across ranks due to data corruption. Which diagnostic evidence should be obtained FIRST to substantiate the likely fault or configuration gap? Select ONE best answer.
- Inspect nccl-tests output verification flags, message sizes, GPU logs and reproducible error traces.
- Inspect RDMA device state, NCCL transport logs, port counters, rank mapping and cross-node bandwidth.
- Inspect multipath state, controller events, write integrity hashes, remount logs and recovery timing.
- Publish NCCL throughput numbers despite reported data-validation errors or hanging communicator ranks.
Explanation
Correct Answer
A:This is the direct operational evidence to investigate: Inspect nccl-tests output verification flags, message sizes, GPU logs and reproducible error traces. Observed scenario: A communication test reports high transfer speed but distributed results differ across ranks due to data corruption.
Incorrect Answers
B:That option concerns Inter-node NCCL east-west RDMA readiness. Collective performance is not useful when data integrity or communicator completion fails.
C:This alternative is relevant to Storage redundancy failover and data consistency but does not directly resolve the current NCCL device buffers and data integrity checks issue: Inspect multipath state, controller events, write integrity hashes, remount logs and recovery timing. Observed scenario: A communication test reports high transfer speed but distributed results differ across ranks due to data corruption.
D:This tempting but unsafe shortcut is not a sufficient remediation for NCCL device buffers and data integrity checks: Publish NCCL throughput numbers despite reported data-validation errors or hanging communicator ranks. A communication test reports high transfer speed but distributed results differ across ranks due to data corruption.
Question 760
During an NVIDIA AI factory acceptance test, engineers discover: A communication test reports high transfer speed but distributed results differ across ranks due to data corruption. Which TWO complementary elements are needed: the correct technical action and the strongest independent diagnostic evidence? Select TWO answers.
- Publish NCCL throughput numbers despite reported data-validation errors or hanging communicator ranks.
- Validate collective correctness over representative sizes and iteration counts alongside throughput.
- Inspect nccl-tests output verification flags, message sizes, GPU logs and reproducible error traces.
- Run supported single-node NCCL collectives spanning the intended local GPUs and compare with baseline topology.
- Inspect NCCL debug traces, selected network plugin, environment variables and host network topology.
Explanation
Correct Answers
B:This is an appropriate correction for NCCL device buffers and data integrity checks: Validate collective correctness over representative sizes and iteration counts alongside throughput. Observed scenario: A communication test reports high transfer speed but distributed results differ across ranks due to data corruption. The governing mechanism is: Collective performance is not useful when data integrity or communicator completion fails.
C:This is the direct operational evidence to investigate: Inspect nccl-tests output verification flags, message sizes, GPU logs and reproducible error traces. Observed scenario: A communication test reports high transfer speed but distributed results differ across ranks due to data corruption. The governing mechanism is: Collective performance is not useful when data integrity or communicator completion fails.
Incorrect Answers
A:This tempting but unsafe shortcut is not a sufficient remediation for NCCL device buffers and data integrity checks: Publish NCCL throughput numbers despite reported data-validation errors or hanging communicator ranks. A communication test reports high transfer speed but distributed results differ across ranks due to data corruption. Collective performance is not useful when data integrity or communicator completion fails.
D:That option concerns Intra-node NCCL all-reduce test scope. Collective performance is not useful when data integrity or communicator completion fails.
E:This alternative is relevant to NCCL transport environment and benchmark reproducibility but does not directly resolve the current NCCL device buffers and data integrity checks issue: Inspect NCCL debug traces, selected network plugin, environment variables and host network topology. Observed scenario: A communication test reports high transfer speed but distributed results differ across ranks due to data corruption.