🎯Core Definition
Test-time compute scaling spends more compute at generation time to buy accuracy, orthogonal to training-time scaling laws. Main forms: ① thinking budgets — o1-style slow thinking that explicitly generates long CoTs; more allowed tokens → higher accuracy (an inference-time scaling law); ② sampling-and-selecting — Best-of-N with a reward model, or majority voting; ③ parallel search — MCTS with process rewards. Budgets are controlled via reasoning effort (low/medium/high) or max_tokens.
💡Use Cases
verifiable or scorable tasks like math and code; latency-tolerant high-stakes settings; API users tuning effort for cost-performance; and distilling searched high-quality trajectories back into small models via self-play.
⚡Key Problems Solved
"answer in one shot" is inaccurate on hard tasks; test-time compute shifts FLOPs from training to inference, boosting hard-task accuracy without retraining, along a compute-time tradeoff curve where error falls by a power law with diminishing returns.