qGAMMA: A Framework for Optimal DNN Mapping on Multi-Precision Accelerators
Authors: Leandro Fiorin, Luigi Altamura, Cristina Silvano
Organizations: Dipartimento di Elettronica e Informazione, Politecnico di Milano, Milano, Italy. · Department of Computer Science and Engineering, Chalmers University of Technology and University of Gothenburg, SE-41296 Gothenburg, Sweden
This work describes qGAMMA, a flexible framework for exploring and optimizing the mapping of mixed-precision Deep Neural Network (DNN) models onto general-purpose spatial accelerators that support a range of fixed- and floating-point precisions. qGAMMA navigates the design space using a domain-specific genetic algorithm and an analytical performance model based on hardware synthesis results. The framework identifies the optimal mapping and accelerator configuration that minimizes target metrics. Extensive evaluations across DNN workloads show that qGAMMA offers valuable insights for designing mixed-precision applications, enabling better trade-offs between performance, energy efficiency, and resource utilization.
Figures & tables
Figure 1: An example of (a) CNN computation and (b) dataflow structure.
Framework
Exploration method
Mult. precision models
Mixed-precision
Timeloop [ 12 ]
Random sampling
Yes
No
GAMMA [ 9 ]
Genetic algorithm
No
No
LOMA [ 14 ]
Constrained brute-force
No
No
CoSA [ 6 ]
Mixed ILP formulation
No
No
SALSA [ 8 ]
Simulated annealing
No
No
This work
Genetic algorithm + heuristics
Yes
Yes
Table 1: Comparison of mapping frameworks’ characteristics in previous works and this work. qGAMMA is the first tool to support mixed-precision mapping on multi-precision spatial architectures.
Figure 3: Overview of the proposed framework: The red boxes highlight the key technical contributions of this study.
Figure 4: (a) Example of encoding for a 3-level genome and corresponding dataflow; (b) dataflow modelling of an INT8 operation in the proposed functional unit model.
Figure 5: (a) Latency and (b) number of generations observed for the mixed-precision ResNet18 optimized for minimum latency, when using the heuristics implemented in qGAMMA, and without them (original GAMMA search algorithm). The graphs include the generations needed to implement the early-stop. Per-layer precision is shown in Figure 5(a) .
Figure 6: (a) EDP and (b) latency of a ResNetV1 optimized for minimum EDP, considering three uniform floating-point precisions and per-layer optimization.
Figure 7: (a) Energy and (b) latency of a MobileNetV1 optimized for minimum energy, considering three uniform integer fixed-point precisions and single-cluster optimization.
Figure 8: Comparison of (a) latency and (b) energy consumption between a mixed-precision (INT8, INT4) ResNet18 and a single-precision (INT8) ResNet18, both optimized for minimum latency with single clustering optimization.
Mixed-precision computation has been introduced in deep neural networks (DNNs) as an effective approach to reduce latency, energy consumption, and memory footprint. However, efficiently mapping mixed-precision networks onto multi-precision spatial architectures poses several challenges. These include determining the appropriate precision for each layer, balancing layer-wise accuracy sensitivity to quantization against architectural heterogeneity and system-level constraints, and accurately estimating the system-level cost of heterogeneous precision assignments. This work presents SEADA, an efficient methodology designed to address these challenges. SEADA comprises: (i) a configurable system-level analytical cost model of a multi-precision spatial accelerator architecture; (ii) a fast mapping tool that identifies near-optimal mappings of DNN workloads onto the target integer accelerator; (iii) analytical models for floating-point layers to estimate the overall benefits of mixed-precision execution; and (iv) a per-layer precision selection methodology based on bit-level entropy, enabling efficient assignment across multiple numerical precisions. SEADA's efficiency provides designers with a robust framework for the design-space exploration of multi-precision architectures.
Leandro Fiorin, Marco Ronzani, Cristina Silvano
Indipendent Researcher Groningen, The Netherlands · Dipartimento di Elettronica e Informazione, Politecnico di Milano. Milano, Italy
Deploying deep neural networks on resource-constrained 6G edge devices demands aggressive compression with minimal accuracy loss. Quantization-Aware Training (QAT) has emerged as a leading compression approach; however, existing mixed-precision methods typically operate at coarse layer- or channel-level granularity. These methods often rely on heuristic or search-based bit-allocation strategies, which may overlook fine-grained variability at the neuron level. We propose Neuron-Level Mixed-Precision QAT (NMP-QAT), where each neuron independently learns its own discrete precision during training. Starting from low-bit precision, NMP-QAT expands bit-width only when training signals demand it, via differentiable surrogates and straight-through estimators, while preserving a fully discrete inference graph. This adaptability extends to both weights and activations, reducing memory movement. Evaluated on telecom and non-telecom datasets across MLP and tabular foundation model architectures, NMP-QAT achieves superior compression-accuracy trade-offs over mixed-precision QAT baselines, making it well-suited for Green AI deployments at the network edge.
Ayush K. Varshney, Konstantinos Vandikas, Šarūnas Girdzijauskas +2
Ericsson Research, Ericsson AB, Stockholm, Sweden · KTH Royal Institute of Technology, Stockholm, Sweden · RISE Research Institutes of Sweden, Stockholm, Sweden
Mixed-precision quantization improves the budget--accuracy trade-off for large language models (LLMs) by allocating more bits to sensitive modules. However, automating this allocation at LLM scale faces a unique combination of constraints: learnable approaches require quantization-aware training, which is infeasible for billion-parameter models; training-free alternatives rely on static proxy metrics that miss cross-module interactions and must be recomputed per target budget; and search-based methods are expensive without guaranteeing exact budget compliance. We propose GAMMA, a quantizer-agnostic framework that learns module-wise precision preferences entirely within a post-training pipeline. GAMMA optimizes a teacher-forced hidden-state reconstruction objective under an augmented Lagrangian constraint, and projects the learned preferences into exact budget-feasible discrete assignments via integer programming. A key property is score reuse: because the learned preferences encode a stable sensitivity ranking rather than budget-specific weights, a single training run serves arbitrary deployment targets by re-solving only the integer program, reducing per-budget adaptation from hours to a few minutes. Across Llama and Qwen models (8B--32B), GAMMA outperforms both fixed-precision baselines (up to +12.99 Avg.) and search-based mixed-precision methods (up to +7.00 Avg.), and can match fixed 3-bit quality at 2.5-bit average precision, enabling deployment at substantially smaller memory footprints.
Zhangyang Yao, Haiyan Zhao, Haoyu Wang +3
Beihang University · Tsinghua University · ByteDance Inc