BIDENT: Heterogeneous Operator-level Mapping for Efficient Edge Inference
Modern edge System-on-Chips (SoCs) integrate heterogeneous processing units (PUs) such as CPUs, GPUs, and NPUs, yet current inference stacks map entire models to a single PU, leaving significant performance and energy efficiency on the table. This is exacerbated by emerging architectures such as state-space models (SSMs), Kolmogorov-Arnold networks (KANs), and multi-stage vision-language-action (VLA) pipelines, whose diverse operator characteristics are not uniformly suited to any single PU. We present BIDENT, a unified operator-level orchestration framework for heterogeneous edge inference that maps individual operators to the most suitable PU based on profiled execution characteristics. BIDENT formulates operator-to-PU assignment as a shortest-path problem over a weighted execution graph, enabling efficient and optimal scheduling under the cost model for both latency- and energy-minimization objectives. Unlike prior work relying on model-specific heuristics or coarse-grained partitioning, BIDENT is model-agnostic and jointly supports sequential execution, intra-model parallelism across independent operators, and multi-model concurrent scheduling in a single formulation. We implement BIDENT on an Intel Core Ultra SoC and evaluate it across 10 model families spanning CNNs, Transformers, SSMs, KANs, spiking networks, and multi-stage pipelines. BIDENT achieves up to 1.60x speedup via intra-model parallelism and a 3.42x geometric mean speedup across 190 multi-model combinations by utilizing otherwise idle compute. Sequential heterogeneous mapping yields more modest gains (up to 1.58x, 1.09x geometric mean), while energy-aware scheduling reduces energy consumption by 48.2% on average in concurrent settings. These results show that operator-level orchestration, not model-level mapping, is the key abstraction for fully exploiting heterogeneity in next-generation edge AI.