---
id: pr-vllm-38479
repo: vllm-project/vllm
pr: 38479
title: '[Attention Backend] TurboQuant: 2-bit KV cache compression with 4x capacity'
author: vibhavagarwal5
date: '2026-04-15'
url: https://github.com/vllm-project/vllm/pull/38479
source_category: upstream-code
architectures:
- sm100
- sm90
tags:
- attention
- decode
- quantization
techniques: []
hardware_features: []
kernel_types:
- attention
- decode
- quantization
languages:
- cuda-cpp
- triton
captured_at: '2026-04-17'
status: merged
merge_sha: f4b42df04847dcbd3247f7f4c56dff45e40bdf0d
inclusion_reason: kernel file changes
changed_paths:
- .buildkite/test_areas/lm_eval.yaml
- docs/design/attention_backends.md
- pyproject.toml
- tests/evals/gsm8k/configs/Qwen3-4B-TQ-k3v4nc.yaml
- tests/evals/gsm8k/configs/Qwen3-4B-TQ-k8v4.yaml
- tests/evals/gsm8k/configs/Qwen3-4B-TQ-t3nc.yaml
- tests/evals/gsm8k/configs/Qwen3-4B-TQ-t4nc.yaml
- tests/evals/gsm8k/configs/models-turboquant.txt
- tests/quantization/test_turboquant.py
- vllm/config/attention.py
- vllm/config/cache.py
- vllm/engine/arg_utils.py
- vllm/model_executor/layers/attention/attention.py
- vllm/model_executor/layers/quantization/turboquant/__init__.py
- vllm/model_executor/layers/quantization/turboquant/centroids.py
- vllm/model_executor/layers/quantization/turboquant/config.py
- vllm/model_executor/layers/quantization/turboquant/quantizer.py
- vllm/platforms/cuda.py
- vllm/platforms/xpu.py
- vllm/utils/torch_utils.py
- vllm/v1/attention/backends/registry.py
- vllm/v1/attention/backends/turboquant_attn.py
- vllm/v1/attention/ops/triton_turboquant_decode.py
- vllm/v1/attention/ops/triton_turboquant_store.py
- vllm/v1/core/single_type_kv_cache_manager.py
- vllm/v1/kv_cache_interface.py
- vllm/v1/worker/utils.py
head_ref_oid: ac46a983ef7ab8d8c23f058f04bc2493feef7109
artifact_dir: evidence/pull-bundles/vllm/gh-38479
---
# [Attention Backend] TurboQuant: 2-bit KV cache compression with 4x capacity

- Repository: `vllm-project/vllm`
- PR: [38479](https://github.com/vllm-project/vllm/pull/38479)
- Decision: `kernel file changes`
- Reason: kernel file changes

## Changed Paths

- `.buildkite/test_areas/lm_eval.yaml`
- `docs/design/attention_backends.md`
- `pyproject.toml`
- `tests/evals/gsm8k/configs/Qwen3-4B-TQ-k3v4nc.yaml`
- `tests/evals/gsm8k/configs/Qwen3-4B-TQ-k8v4.yaml`
- `tests/evals/gsm8k/configs/Qwen3-4B-TQ-t3nc.yaml`
- `tests/evals/gsm8k/configs/Qwen3-4B-TQ-t4nc.yaml`
- `tests/evals/gsm8k/configs/models-turboquant.txt`
- `tests/quantization/test_turboquant.py`
- `vllm/config/attention.py`
- `vllm/config/cache.py`
- `vllm/engine/arg_utils.py`
- `vllm/model_executor/layers/attention/attention.py`
- `vllm/model_executor/layers/quantization/turboquant/__init__.py`
- `vllm/model_executor/layers/quantization/turboquant/centroids.py`
- `vllm/model_executor/layers/quantization/turboquant/config.py`
- `vllm/model_executor/layers/quantization/turboquant/quantizer.py`
- `vllm/platforms/cuda.py`
- `vllm/platforms/xpu.py`
- `vllm/utils/torch_utils.py`
- `vllm/v1/attention/backends/registry.py`
- `vllm/v1/attention/backends/turboquant_attn.py`
- `vllm/v1/attention/ops/triton_turboquant_decode.py`
- `vllm/v1/attention/ops/triton_turboquant_store.py`
- `vllm/v1/core/single_type_kv_cache_manager.py`
- `vllm/v1/kv_cache_interface.py`
- `vllm/v1/worker/utils.py`

## Evidence Bundle

`evidence/pull-bundles/vllm/gh-38479`
