QUILL: An Algorithm–Architecture Co-Design for Cache-Local Deformable Attention

Deformable Transformers achieve state-of-the-art object detection, but deformable attention maps poorly to hardware due to irregular memory access and low arithmetic intensity. We present QUILL, a schedule-aware accelerator that makes MSDeformAttn cache-local and single-pass. QUILL’s Distance-based Out-of-Order Querying (DOOQ) reorders queries by spatial proximity, enabling a look-ahead, double-buffered prefetch that overlaps memory and compute. QUILL also uses a fused MSDeformAttn pipeline that performs interpolation, Softmax, aggregation, and output projection in one pass, avoiding intermediate spills and keeping small tensors on-chip. Implemented in RTL and evaluated end-to-end, QUILL achieves up to 7.29× higher throughput and 47.3× better energy efficiency than an RTX 4090, and improves throughput/energy efficiency over prior accelerators by 3.26–9.82× / 2.01–6.07×. With mixed precision, accuracy stays within ≤ 0.9 AP of FP32 across Deformable and Sparse DETR variants. By converting sparsity into locality and locality into utilization, QUILL delivers consistent end-to-end gains.