pico-gpu

pico-gpu holds the CUDA kernels of the Pico zkVM: GPU trace generation for Pico's RISC-V, precompile and recursion chips, and the GPU side of Pico's multilinear prover (LogUp-GKR, zerocheck, stacked reduction, WHIR).

⚠️ Disclaimer: This project is still a work in progress and is evolving quickly. It has not been audited and is not recommended for production use; use it at your own risk.

How it is built

pico-gpu is a source library for Pico and is not built on its own. The Rust crate in rust/ contains no code: through its links key it hands the location of this repository (DEP_PICO_GPU_ROOT) to the Pico crates that depend on it, and those crates compile the kernels when Pico is built with its GPU feature:

Pico crate	Compiles	Into
cuda-mle	src/prover/ and the NTT sources in third_party/sppark/	the static libraries cuda_kb_all and mle-kernels
gpu-api	its own compilation units, which include the headers in src/tracegen/	the trace-generation library

Every source includes the others by its path from src/ ("field/fp.h", "tracegen/riscv/cpu.cuh"), so src/ is the only include root besides the sppark directories.

To build Pico with GPU proving, follow Pico's documentation; the GPU feature is cuda-mle, for example:

cargo build --release --bin mle-single-node --features "cuda-mle bigint-rug tcmalloc mmap-memory"

GPU targets:

• cuda-mle compiles for the compute capability of the first GPU nvidia-smi reports, plus PTX. Set CUDA_ARCH (e.g. CUDA_ARCH=120, comma-separated for several) to choose the targets yourself, for instance on a build machine without a GPU.
• gpu-api embeds PTX that the driver compiles when the library loads. Set GPU_TARGET_ARCHS (e.g. GPU_TARGET_ARCHS=120) to compile it ahead of time instead.

Requirements

• Linux, an NVIDIA GPU and its driver (nvidia-smi on PATH)
• CUDA Toolkit with nvcc on PATH, recent enough for your GPU
• The Rust toolchain pinned by Pico's rust-toolchain

Tested with CUDA 13 on GeForce RTX 5090 (compute capability 12.0).

Repository layout

Path	Contents
src/common/	Launch helpers, error handling, out-of-memory recovery, shared device utilities
src/field/	KoalaBear field and extensions: kb31_t (trace generation) and fp.h / fpext.h (prover)
src/hash/poseidon2/	KoalaBear width-16 Poseidon2: the trace-generation kernels and the prover's hashing, sharing one parameter header
src/prover/	Multilinear prover kernels: sumcheck, WHIR, stacked reduction, Merkle commitment, sponge
src/prover/dag/	Encoding and evaluation of the constraint DAG
src/prover/logup_zerocheck/	LogUp-GKR and zerocheck kernels
src/prover/ntt/	Small in-kernel NTTs and the Reed-Solomon encoding fast path
src/tracegen/	Trace generation, grouped into common/, riscv/, precompiles/ and recursion/
third_party/sppark/	Code derived from sppark (Apache-2.0), see its README
rust/	The pico-gpu crate that exports this repository's location to Pico

Security

If you discover a security vulnerability, please see SECURITY.md for responsible disclosure instructions.

Acknowledgements

pico-gpu builds on prior work in GPU-accelerated zero-knowledge proving:

• sppark: Portions of this library, especially in third_party/sppark/, src/common/ and src/field/kb31_t.hpp, are ported and adapted from the sppark project, licensed under the Apache License 2.0 (see third_party/sppark/LICENSE).
• SP1: Parts of pico-gpu's trace-generation design are inspired by SP1.
• Plonky3: pico-gpu's Poseidon2 kernels use Plonky3's KoalaBear parameters and match its permutation bit for bit.
• OpenVM: Parts of pico-gpu's multilinear prover kernels are adapted from OpenVM's stark-backend, licensed under MIT or Apache-2.0.

License

Licensed under either of Apache License, Version 2.0 or MIT license at your option, except for the code derived from third-party projects, which keeps its original licence:

• sppark (Apache-2.0, see third_party/sppark/LICENSE): third_party/sppark/, src/common/device_ptr.hpp, src/common/exception.hpp, src/common/exception.cuh, src/common/rusterror.h and src/field/kb31_t.hpp.
• RISC Zero (Apache-2.0), by way of OpenVM: src/field/fp.h and src/field/fpext.h.
• OpenVM stark-backend (MIT or Apache-2.0, Copyright (c) 2025 The OpenVM Authors): parts of src/prover/, src/common/launcher.cuh and src/common/utils.cuh.