---
id: pr-vllm-40177
repo: vllm-project/vllm
pr: 40177
title: Add nvfp4 kv cache support
author: sychen52
date: '2026-05-01'
url: https://github.com/vllm-project/vllm/pull/40177
source_category: upstream-code
architectures:
- sm100
tags:
- FlashInfer
- attention_kv
- blackwell
- fp4
- fp8
- gemm_quant
- memory_primitives
- nvfp4
- paged attention
- sm100
techniques:
- cache-policy
- fine-grained-quantization
hardware_features:
- blackwell
- fp4
- fp8
- nvfp4
kernel_types:
- attention
- gemm
- memory
languages:
- cuda-cpp
captured_at: '2026-05-16'
status: merged
merge_sha: 947138b6c22f9a4751b63b9aa75a2bc4b42835e9
inclusion_reason: Preserve page/KV/layout and plan-run contracts; profile memory traffic separately from math utilization.
changed_paths:
- docs/design/attention_backends.md
- tests/kernels/attention/test_flashinfer_trtllm_attention.py
- tests/v1/attention/test_trtllm_attention_integration.py
- tools/pre_commit/generate_attention_backend_docs.py
- vllm/config/vllm.py
- vllm/model_executor/layers/quantization/modelopt.py
- vllm/v1/attention/backends/flashinfer.py
- vllm/v1/kv_cache_interface.py
artifact_dir: evidence/pull-bundles/vllm/gh-40177
head_ref_oid: 6ac6a3023aac2fadfd98893fdf0951fa8f284bb1
---
# Add nvfp4 kv cache support

- Repository: `vllm-project/vllm`
- PR: [40177](https://github.com/vllm-project/vllm/pull/40177)
- Decision: `Preserve page/KV/layout and plan-run contracts; profile memory traffic separately from math utilization.`
- Reason: Preserve page/KV/layout and plan-run contracts; profile memory traffic separately from math utilization.

## Changed Paths

- `docs/design/attention_backends.md`
- `tests/kernels/attention/test_flashinfer_trtllm_attention.py`
- `tests/v1/attention/test_trtllm_attention_integration.py`
- `tools/pre_commit/generate_attention_backend_docs.py`
- `vllm/config/vllm.py`
- `vllm/model_executor/layers/quantization/modelopt.py`
- `vllm/v1/attention/backends/flashinfer.py`
- `vllm/v1/kv_cache_interface.py`

## Evidence Bundle

`evidence/pull-bundles/vllm/gh-40177`
