Patterns
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Energy-Efficient Inference(EEI)

Optimizes AI inference for minimal energy consumption while maintaining performance

Complexity: highPattern

Core Mechanism

Energy‑Efficient Inference minimizes joules per output while maintaining accuracy and latency by combining model compression (quantization, pruning, distillation), adaptive computation (early exit, dynamic depth, token and attention sparsity), optimized kernels (e.g., FlashAttention), and hardware‑aware serving (continuous/dynamic batching, KV‑cache policies, and power/thermal limits). The goal is to deliver required quality using the least energy per request or token on the target device or cluster.

Workflow / Steps

  1. Baseline and targets: measure latency, throughput, accuracy, and energy (J/request or J/token).
  2. Compress the model: apply PTQ/QAT (INT8/INT4, activation‑aware), pruning (structured), and distillation.
  3. Enable adaptive compute: early‑exit or dynamic depth; selective compute for hard spans; speculative decoding.
  4. Optimize kernels/memory: use efficient attention, KV‑cache paging/quantization, and operator fusion.
  5. Serving & batching: use continuous/dynamic batching within SLO; right‑size concurrency and placement.
  6. Hardware tuning: prefer low‑precision tensor cores/NPU; cap clocks/boost by SLO; manage thermal throttling.
  7. Monitor & iterate: track energy, tokens/s, accuracy drift; rollback if energy savings hurt SLOs/quality.

Best Practices

Start with PTQ on weights and activations (INT8/INT4); use activation‑aware or smooth quantization to preserve accuracy.
Combine structured pruning with distillation; validate on downstream tasks, not only pretraining metrics.
Adopt efficient attention kernels (e.g., FlashAttention) and paged/quantized KV cache to cut memory traffic.
Use early‑exit/dynamic depth and token/attention sparsity to reduce compute on easy inputs.
Batch aggressively when latency budgets allow; otherwise use micro‑batches and streaming.
Pin models to hardware that supports low‑precision acceleration; avoid precision up/down casts in hot paths.
Continuously profile power (NVML/DCGM, RAPL) alongside p95 latency and accuracy to avoid regressions.

When NOT to Use

  • Applications requiring strict numerical fidelity or determinism incompatible with low precision.
  • Hard real‑time deadlines where batching/verification (e.g., speculative decoding) violates SLOs.
  • Compliance‑critical domains where model changes (quantization/pruning) need lengthy re‑validation.

Common Pitfalls

  • Over‑quantization or uncalibrated activations causing large accuracy drops on downstream tasks.
  • Unstructured pruning that yields sparse tensors unsupported by the target hardware kernels.
  • Ignoring memory bandwidth/KV‑cache pressure; FLOP reductions alone may not save energy.
  • Measuring only watts, not energy per useful output (J/request, J/token) and user‑perceived latency.

Key Features

Low‑precision execution (INT8/INT4) with activation‑aware calibration
Structured pruning and knowledge distillation to smaller students
Efficient attention kernels and KV‑cache optimization
Adaptive computation: early exit, dynamic depth, token/attention sparsity
Continuous/dynamic batching and streaming for utilization
Power/thermal‑aware scheduling and placement

KPIs / Success Metrics

  • Energy: joules per request and per output token; average and p95 watts under load.
  • Latency/TTFT/TPOT: p50/p95 latency and time‑to‑first‑token/time‑per‑output‑token.
  • Throughput/utilization: tokens per second; GPU SM and memory utilization; batch effectiveness.
  • Quality: task accuracy/human ratings vs. baseline; drift post‑compression.
  • Stability: OOM/retry rate, thermal throttling incidence, autoscale convergence time.

Token / Resource Usage

  • Quantize weights/activations and optionally KV cache; track memory footprint per concurrent stream.
  • Adopt efficient attention and cache paging to reduce DRAM traffic (often dominant energy component).
  • Cap context length and use compression/summarization; prefer streaming to avoid long stalls.
  • Tune batch size/concurrency to maximize tokens/s within SLO and thermal/power envelopes.

Best Use Cases

  • Edge/mobile inference with battery and thermal limits; intermittent connectivity.
  • High‑volume serving where energy and cost per token dominate (contact center, summarization).
  • On‑prem/colo deployments with fixed power caps; sustainability‑driven SLAs.

References & Further Reading

Patterns

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