HSCO-Bench: An Agent-Driven End-to-End Hardware-Software Co-design Benchmark for Systems-on-Chip

Large language models (LLMs) are increasingly adopted for software and hardware design, yet these domains are still evaluated separately. Software benchmarks typically assume fixed hardware targets, while hardware benchmarks focus on component-level optimization without considering the full hardware-software stack. Consequently, no existing benchmark evaluates whether an LLM agent can perform end-to-end, system-level hardware-software co-design. Such a process requires: 1) analyzing applications to identify kernels requiring acceleration, 2) designing and \emph{integrating} heterogeneous accelerators into a System-on-Chip (SoC) under resource constraints, and 3) mapping kernels onto the generated accelerators. We present \hsco{}, an end-to-end hardware-software co-design benchmark for accelerator-rich heterogeneous SoC generation. Built upon an open-source SoC platform with a curated repository structure, HSCO-Bench evaluates the ability of LLMs to jointly optimize software and hardware stacks, producing SoC prototypes deployed on the AMD Virtex-7 FPGA VC707 Evaluation Kit. Experimental results show that end-to-end integration remains challenging for current models, with widespread failures. Among the five frontier models evaluated, only two of them could successfully generate valid SoC prototypes. Yet, even in these successful instances, the generated designs are far from optimal. While we observe a promising peak speedup of 16.22x, the maximum additional resource utilization reaches only 23.67%. This highlights that while state-of-the-art models demonstrate an emerging capability for hardware acceleration, they still heavily underutilize the available hardware capacity, leaving substantial room for future optimization. To the best of our knowledge, HSCO-Bench is the first benchmark targeting this complete co-design flow, enabling LLMs to jointly reason about and modify both the software and hardware stacks of heterogeneous SoCs.