EvanOLeary/pallasbench-robust-gpu-a100

PallasBench: Robust Pallas GPU Kernel Benchmark (A100)

39/45 kernels passing on NVIDIA A100 80GB -- the first GPU-focused evaluation of JAX Pallas kernels.

What is this?

PallasBench is a suite of 45 JAX Pallas kernels across 3 difficulty levels. The original kernels were designed for TPU and failed on GPU because Pallas compiles to Triton on NVIDIA hardware, which has strict block size limits that TPU's Mosaic compiler does not.

We fixed all 45 kernels for GPU compatibility and evaluated them on an A100 with correctness checking, timing, and compilation profiling.

Why does this matter?

Pallas is the only kernel DSL that targets both GPU and TPU from a single source. There are many CUDA and Triton kernel benchmarks (KernelBench, robust-kbench, KernelBot), but no Pallas benchmark existed with GPU results. This dataset fills that gap.

The kernels are correct but unoptimized -- they represent what an LLM would generate when writing Pallas code without GPU-specific tuning. This makes them ideal as the initial population for evolutionary kernel optimization (e.g., ShinkaEvolve).

Inspiration

This work follows the methodology of:

• SakanaAI/AI-CUDA-Engineer-Archive -- CUDA kernel archive with profiling data
• robust-kbench -- robust kernel evaluation with anti-gaming filters
• KernelBench -- LLM kernel generation benchmark

We adapt their evaluation methodology to the JAX/Pallas compilation pipeline.

The GPU Fix

PallasBench kernels used TPU-sized blocks like (1024, 4096) = 4M elements per block. On GPU, Pallas compiles through Triton, which:

• Limits blocks to 1,048,576 elements
• Unrolls the block into PTX instructions (1M elements = 10MB PTX = hours of ptxas compilation)
• Has 164KB shared memory per SM (vs 16-32MB VMEM on TPU)

Our fix: 2D tiling with (128, 128) or (16, 16) blocks depending on the kernel pattern. This reduces PTX size from 10MB to ~300KB and compile time from hours to seconds.

Results Summary

Level	Total	Pass	Error	Skip
L1: Single ops	27	25	1	0
L2: Fused patterns	13	10	2	0
L3: Architecture	5	3	1	2
Total	45	39 (87%)	4	2

Remaining failures

Kernel	Issue	Root cause
embedding_lookup	Triton non-array ops	Integer indexing not supported in Triton
pwm_scan	Triton non-array ops	Scan with non-array state
pairwise_distance	reduce_sum lowering	Nested reduction not supported
triangle_update	reduce_sum lowering	Same
gated_mlp	Weight matrices >1M elements	Would need K-tiled accumulator loop
transformer_block	Combines all patterns	Needs full decomposition

These are JAX/Triton integration limitations, not block size issues.

Files

File	Description
	Complete results for all 45 kernels
	SakanaAI/AI-CUDA-Engineer-Archive compatible format
	Complete git diff of all GPU fixes
	Robust evaluation framework (5 filters, tiling analysis, IR capture)
	Pre-fix kernel source (TPU-oriented)
	GPU-compatible kernel source

SakanaAI Format Schema

Each row in contains:

Field	Type	Description
Op_Name	string	Kernel name (e.g. relu, flash_attention)
Level_ID	int	1-3
Task_ID	int	Sequential ID
Pallas_Runtime	float	Kernel execution time (ms), includes JIT
JAX_Baseline_Runtime	float	JAX jnp baseline time (ms)
Pallas_Speedup	float	baseline / kernel
Pallas_Code	string	Full fixed Pallas kernel source
Pallas_Code_Original	string	Original TPU-oriented source
JAX_Baseline_Code	string	JAX reference implementation
Correct	bool	Matches baseline within atol=1e-3
Error	string	Error message if failed
Target_Hardware	string	NVIDIA A100 80GB PCIe
Framework	string	jax.experimental.pallas
Backend	string	triton
Fix_Applied	string	Type of fix (2D tiling, block_rows clamped, etc)

Hardware

Component	Specification
GPU	NVIDIA A100 80GB PCIe
SMs	108
HBM Bandwidth	2,039 GB/s
L2 Cache	40 MB
Shared Memory	164 KB/SM
Compute	8.0
Instance	Azure Standard_NC24ads_A100_v4
RAM	216 GB
JAX	0.10.1
Triton	3.7.0

Provenance

• Source: PallasBench by Tyronita
• Evaluation methodology: Adapted from robust-kbench by SakanaAI
• Dataset format: Follows AI-CUDA-Engineer-Archive schema

Citation

Need exactly one file argument

License

Apache 2.0