Turning Opportunistic AI Inference Capacity Into Better Ads Recommendations

Meta has built a system that repurposes locally idle inference capacity across its fleet to improve ads recommendations. The system aggregates preemptible, volatile capacity pockets into a shared opportunistic pool and applies two elasticity levers: Rank More Ads (RMA), which increases candidates evaluated by ranking stages, and Serve Better Models (SBM), which routes more requests to a more powerful model. Physical and logical isolation plus value-aware load shedding protect baseline serving performance.