arXiv Machine Learning

Amplifying Latency and Cost of LLM Inference via Rowhammer Attack

The paper introduces LLVMhammer, a Rowhammer attack that induces a bit‑flip in Triton’s MLIR/LLVM compilation pipeline, causing the generation of a suboptimal GPU kernel that persists across inference runs. A single successful bit‑flip can increase LLM inference latency by 4–16 % on NVIDIA RTX 4090 and AMD RX 7900 XTX GPUs, and can also degrade output quality, lowering BERTScore to as low as 25 %. The attack is GPU‑vendor‑agnostic and demonstrates that memory corruption in the compiler can have lasting performance and security impacts on large‑language‑model inference.

arXiv Machine Learning
Sep 23

Accelerating the Mitigation of LLM Inference Nondeterminism Across GPU Architectures

The paper addresses the problem of non‑deterministic outputs from large language models (LLMs) when run on different GPU architectures, caused by floating‑point non‑associativity and hardware‑dependent kernel choices. It proposes a set of fixed‑configuration fused‑upcast GEMM kernels that load 16‑bit weights, upcast to FP32, and perform IEEE‑754 compliant reductions in a problem‑shape‑dependent order, ensuring identical linear‑layer outputs across NVIDIA Ampere, Ada, and Hopper GPUs. The new approach achieves 1.17–3.1× faster end‑to‑end performance than existing solutions and halves weight‑memory traffic while maintaining cross‑architecture reproducibility.

By Liam Cooper, Shinnung Jeong, Hyeran Jeon, Jeffrey Young, Hyesoon Kim
arXiv AI
Aug 28

Pushing the Envelope of LLM Inference with Ultra-Low-Bit Quantized Models

The paper reports the development of 2‑bit microkernels for CPUs and mixed‑precision 2‑bit kernels for Intel Xe2 GPUs, achieving near‑roofline performance. Integrated into LLM inference pipelines, these kernels deliver up to 7× speedup over 16‑bit inference on CPUs and 6.7× on GPUs, surpassing the current state‑of‑the‑art bitnet.cpp runtime by 2.2×. The work demonstrates that ultra‑low‑bit LLM models can be deployed efficiently, offering significant gains in latency, memory, throughput, and energy consumption.

By Evangelos Georganas, Dhiraj Kalamkar, Alexander Heinecke, Pradeep Dubey
arXiv Machine Learning
Jun 2

Bit-Exact AI Inference Verification Without Performance Tradeoffs

arXiv:2606. 00279v1 Announce Type: cross Abstract: Verifying claims about AI workloads is a pre- requisite for credible AI governance of covert adversaries (who comply with monitoring only when detection likelihood is high), yet the ap- parent non-determinism of GPU floating-point arithmetic forces auditors to accept approximate output matches.

By Naci Cankaya
arXiv AI
Sep 25

KernelOPT: Dispatch-Aware Agentic Search for GPU Kernel Optimization

KernelOPT is a multi‑agent system that optimizes GPU kernels generated by compilers like PyTorch Inductor by treating compiled models as structured artifacts. It preserves vendor library calls and focuses on Triton sub‑kernels, using five profiling‑guided LLM agents and a four‑gate verification cascade to ensure correctness and performance before re‑stitching the model. On 250 KernelBench problems, KernelOPT achieves geometric mean speedups of 1.40×, 1.15×, and 1.07× over torch.compile at three optimization levels.

By Aheli Poddar, Sanskar Prasad, Arindam Samanta, Subha Chakraborty, Vishal Goyal, Rohit Singh Rathaur
arXiv AI
Sep 30

AI as a Compiler: Compiling Triton kernels without the Triton compiler

The paper explores using large language models (LLMs) to replace traditional compiler backends, a process termed AI lowering. An LLM agent translates Triton kernels directly into NVIDIA PTX, achieving 0.83x–3.34x the performance of autotuned Triton on a variety of GPUs and ML kernels. The study also extends a PTX verifier to support modern GPU features, highlighting the potential for AI compilers to reduce engineering effort for new hardware.

By Fran\c{c}ois Costa, Charly Castes, Thomas Bourgeat, Azalia Mirhoseini