diff --git a/auto_round/calib_dataset.py b/auto_round/calib_dataset.py
index b4bbf65b5..5b48e814c 100644
--- a/auto_round/calib_dataset.py
+++ b/auto_round/calib_dataset.py
@@ -14,6 +14,8 @@
 
 import json
 import logging
+import multiprocessing
+import os
 import random
 import sys
 
@@ -23,6 +25,7 @@
 from datasets import Dataset, Features, IterableDataset, Sequence, Value, concatenate_datasets, load_dataset
 from torch.utils.data import DataLoader
 
+from . import envs
 from .utils import is_local_path, logger
 
 CALIB_DATASETS = {}
@@ -85,6 +88,30 @@ def apply_chat_template_to_samples(samples, tokenizer, seqlen, system_prompt=Non
     return example
 
 
+def _make_map_fingerprint(dataset, tokenizer, seqlen, apply_chat_template, system_prompt, text_key="text"):
+    """Compute a stable fingerprint for Dataset.map() calls.
+
+    datasets uses dill to serialize the transform function for cache fingerprinting.
+    HuggingFace tokenizer objects are not reliably serializable by dill, causing
+    a random hash to be used each run — which breaks caching entirely.
+
+    This function computes a deterministic fingerprint from stable string
+    identifiers (tokenizer name, seqlen, etc.) so that caching works correctly
+    and subsequent runs can load from disk instead of re-tokenizing in RAM.
+    """
+    import hashlib
+
+    parts = [
+        getattr(dataset, "_fingerprint", "no_fingerprint"),
+        getattr(tokenizer, "name_or_path", type(tokenizer).__name__),
+        str(seqlen),
+        str(apply_chat_template),
+        str(system_prompt),
+        text_key,
+    ]
+    return hashlib.sha256("|".join(parts).encode()).hexdigest()
+
+
 def get_tokenizer_function(tokenizer, seqlen, apply_chat_template=False, system_prompt=None):
     """Returns a default tokenizer function.
 
@@ -154,7 +181,13 @@ def get_pile_dataset(
             logger.error(f"Failed to load the dataset: {error_message}")
         sys.exit(1)
     calib_dataset = calib_dataset.shuffle(seed=seed)
-    calib_dataset = calib_dataset.map(tokenizer_function, batched=True)
+    calib_dataset = calib_dataset.map(
+        tokenizer_function,
+        batched=True,
+        new_fingerprint=_make_map_fingerprint(
+            calib_dataset, tokenizer, seqlen, apply_chat_template, system_prompt, "text"
+        ),
+    )
 
     return calib_dataset
 
@@ -450,7 +483,13 @@ def default_tokenizer_function(examples):
 
     calib_dataset = load_dataset("madao33/new-title-chinese", split=split)
     calib_dataset = calib_dataset.shuffle(seed=seed)
-    calib_dataset = calib_dataset.map(tokenizer_function, batched=True)
+    calib_dataset = calib_dataset.map(
+        tokenizer_function,
+        batched=True,
+        new_fingerprint=_make_map_fingerprint(
+            calib_dataset, tokenizer, seqlen, apply_chat_template, system_prompt, "content"
+        ),
+    )
 
     return calib_dataset
 
@@ -502,7 +541,13 @@ def get_mbpp_dataset(
     import datasets
 
     calib_dataset = datasets.Dataset.from_list(samples)
-    calib_dataset = calib_dataset.map(tokenizer_function, batched=True)
+    calib_dataset = calib_dataset.map(
+        tokenizer_function,
+        batched=True,
+        new_fingerprint=_make_map_fingerprint(
+            calib_dataset, tokenizer, seqlen, apply_chat_template, system_prompt, "text"
+        ),
+    )
 
     return calib_dataset
 
@@ -571,7 +616,13 @@ def load_local_data(data_path):
     import datasets
 
     calib_dataset = datasets.Dataset.from_list(samples)
-    calib_dataset = calib_dataset.map(tokenizer_function, batched=True)
+    calib_dataset = calib_dataset.map(
+        tokenizer_function,
+        batched=True,
+        new_fingerprint=_make_map_fingerprint(
+            calib_dataset, tokenizer, seqlen, apply_chat_template, system_prompt, "text"
+        ),
+    )
     return calib_dataset
 
 
@@ -641,8 +692,8 @@ def select_dataset(dataset, indices):
         return dataset
 
 
-def get_dataset(tokenizer, seqlen, dataset_name="NeelNanda/pile-10k", seed=42, nsamples=512):
-    """Generate a dataset for calibration.
+def _get_dataset_impl(tokenizer, seqlen, dataset_name="NeelNanda/pile-10k", seed=42, nsamples=512):
+    """Internal implementation: generate a dataset for calibration.
 
     Args:
         tokenizer (Tokenizer): The tokenizer to use for tokenization.
@@ -764,6 +815,7 @@ def concat_dataset_element(dataset):
         )
         if do_concat:
             dataset = concat_dataset_element(dataset)
+
         dataset = dataset.filter(filter_func)
         if name in data_lens:
             dataset = select_dataset(dataset, range(data_lens[name]))
@@ -829,6 +881,59 @@ def concat_dataset_element(dataset):
     return dataset_final
 
 
+def get_dataset(tokenizer, seqlen, dataset_name="NeelNanda/pile-10k", seed=42, nsamples=512):
+    """Generate a dataset for calibration.
+
+    Uses a subprocess for preprocessing to ensure all temporary memory is fully
+    reclaimed by the OS when the subprocess exits.  The HuggingFace ``datasets``
+    library automatically caches intermediate results (e.g. ``.map()``,
+    ``.filter()``), so the main process can reload them cheaply after the
+    subprocess finishes.
+
+    Set environment variable ``AR_DISABLE_DATASET_SUBPROCESS=1`` to disable
+    subprocess mode and run preprocessing in the main process.
+
+    Args:
+        tokenizer: The tokenizer to use for tokenization.
+        seqlen (int): The exact sequence length.
+        dataset_name (str, optional): Dataset name(s) separated by commas.
+        seed (int, optional): Random seed for reproducibility. Defaults to 42.
+        nsamples (int, optional): Total number of samples to include. Defaults to 512.
+
+    Returns:
+        Dataset: The processed dataset ready for calibration.
+    """
+    # Allow disabling subprocess mode via environment variable
+    if envs.AR_DISABLE_DATASET_SUBPROCESS:
+        return _get_dataset_impl(tokenizer, seqlen, dataset_name, seed, nsamples)
+
+    # Run preprocessing in a subprocess so all temporary memory is freed on exit.
+    # The HuggingFace datasets cache is warmed up as a side effect.
+    logger.info("Preprocessing calibration dataset in a subprocess to avoid memory leaks...")
+
+    try:
+        if os.name == "nt":
+            raise OSError("fork is not available on Windows")
+
+        ctx = multiprocessing.get_context("fork")
+        p = ctx.Process(
+            target=_get_dataset_impl,
+            args=(tokenizer, seqlen, dataset_name, seed, nsamples),
+        )
+        p.start()
+        p.join()
+
+        if p.exitcode != 0:
+            raise RuntimeError(f"Dataset preprocessing subprocess exited with code {p.exitcode}")
+
+    except Exception as e:
+        logger.warning(f"Subprocess dataset preprocessing failed ({e}), falling back to in-process mode.")
+
+    # (Re-)load the dataset in the main process.  When the subprocess
+    # succeeded the HF datasets cache makes this almost instant.
+    return _get_dataset_impl(tokenizer, seqlen, dataset_name, seed, nsamples)
+
+
 def get_dataloader(tokenizer, seqlen, dataset_name="NeelNanda/pile-10k", seed=42, bs=8, nsamples=512):
     """Generate a DataLoader for calibration using specified parameters.
 
diff --git a/auto_round/envs.py b/auto_round/envs.py
index 7893b6e80..8a731ad10 100644
--- a/auto_round/envs.py
+++ b/auto_round/envs.py
@@ -31,6 +31,7 @@
     in ["1", "true"],
     "AR_OMP_NUM_THREADS": lambda: os.getenv("AR_OMP_NUM_THREADS", None),
     "AR_DISABLE_OFFLOAD": lambda: os.getenv("AR_DISABLE_OFFLOAD", "0").lower() in ("1", "true", "yes"),
+    "AR_DISABLE_DATASET_SUBPROCESS": lambda: os.getenv("AR_DISABLE_DATASET_SUBPROCESS", "0").lower() in ("1", "true"),
     "AR_DISABLE_COPY_MTP_WEIGHTS": lambda: os.getenv("AR_DISABLE_COPY_MTP_WEIGHTS", "0").lower()
     in ("1", "true", "yes"),
 }
diff --git a/docs/environments.md b/docs/environments.md
index 78e71eab7..242d660d7 100644
--- a/docs/environments.md
+++ b/docs/environments.md
@@ -1,5 +1,7 @@
 # AutoRound Environment Variables Configuration
 
+English | [简体中文](./environments_CN.md)
+
 This document describes the environment variables used by AutoRound for configuration and their usage.
 
 ## Overview
@@ -47,6 +49,26 @@ export AR_USE_MODELSCOPE=true
 export AR_WORK_SPACE=/path/to/custom/workspace
 ```
 
+### AR_DISABLE_OFFLOAD
+- **Description**: Forcibly disables the weight offloading feature in `OffloadManager`. Useful during development and debugging to skip all offload/reload overhead.
+- **Default**: `False` (equivalent to `"0"`)
+- **Valid Values**: `"1"`, `"true"`, `"yes"` (case-insensitive) for disabling offload; any other value keeps the default behavior
+- **Usage**: Set this to bypass offloading entirely
+
+```bash
+export AR_DISABLE_OFFLOAD=1
+```
+
+### AR_DISABLE_DATASET_SUBPROCESS
+- **Description**: Disables the use of a subprocess for dataset preprocessing. By default, AutoRound uses a subprocess to ensure all temporary memory is reclaimed by the OS.
+- **Default**: `False`
+- **Valid Values**: `"1"`, `"true"` (case-insensitive) for disabling; any other value for enabling
+- **Usage**: Set this to run dataset preprocessing in the main process
+
+```bash
+export AR_DISABLE_DATASET_SUBPROCESS=true
+```
+
 ## Usage Examples
 
 ### Setting Environment Variables
@@ -108,16 +130,6 @@ else:
     print("AR_LOG_LEVEL is using default value")
 ```
 
-### AR_DISABLE_OFFLOAD
-- **Description**: Forcibly disables the weight offloading feature in `OffloadManager`. Useful during development and debugging to skip all offload/reload overhead.
-- **Default**: `False` (equivalent to `"0"`)
-- **Valid Values**: `"1"`, `"true"`, `"yes"` (case-insensitive) for disabling offload; any other value keeps the default behavior
-- **Usage**: Set this to bypass offloading entirely
-
-```bash
-export AR_DISABLE_OFFLOAD=1
-```
-
 ## Configuration Best Practices
 
 1. **Development Environment**: Set `AR_LOG_LEVEL=TRACE` or `AR_LOG_LEVEL=DEBUG` for detailed logging during development
diff --git a/docs/environments_CN.md b/docs/environments_CN.md
new file mode 100644
index 000000000..7407354cf
--- /dev/null
+++ b/docs/environments_CN.md
@@ -0,0 +1,147 @@
+# AutoRound 环境变量配置
+
+[English](./environments.md) | 简体中文
+
+本文档介绍 AutoRound 使用的环境变量及其配置说明。
+
+## 概述
+
+AutoRound 通过 `envs.py` 模块提供统一的环境变量管理系统，支持懒加载求值与程序化配置。
+
+## 可用环境变量
+
+### AR_LOG_LEVEL
+- **描述**：控制 AutoRound 默认日志级别
+- **默认值**：`"INFO"`
+- **有效值**：`"TRACE"`、`"DEBUG"`、`"INFO"`、`"WARNING"`、`"ERROR"`、`"CRITICAL"`
+- **用途**：通过设置该变量控制 AutoRound 的日志详细程度
+
+```bash
+export AR_LOG_LEVEL=DEBUG
+```
+
+### AR_ENABLE_COMPILE_PACKING
+- **描述**：启用编译打包优化
+- **默认值**：`False`（等价于 `"0"`）
+- **有效值**：`"1"`、`"true"`、`"yes"`（不区分大小写）表示启用；其他值表示禁用
+- **用途**：启用后可在将 FP4 张量打包为 `uint8` 时获得性能优化
+
+```bash
+export AR_ENABLE_COMPILE_PACKING=1
+```
+
+### AR_USE_MODELSCOPE
+- **描述**：控制是否使用 ModelScope 下载模型
+- **默认值**：`False`
+- **有效值**：`"1"`、`"true"`（不区分大小写）表示启用；其他值表示禁用
+- **用途**：启用后将使用 ModelScope 替代 Hugging Face Hub 下载模型
+
+```bash
+export AR_USE_MODELSCOPE=true
+```
+
+### AR_WORK_SPACE
+- **描述**：设置 AutoRound 操作的工作目录
+- **默认值**：`"ar_work_space"`
+- **用途**：指定 AutoRound 存储临时文件和输出结果的自定义目录
+
+```bash
+export AR_WORK_SPACE=/path/to/custom/workspace
+```
+
+### AR_DISABLE_OFFLOAD
+- **描述**：强制禁用 `OffloadManager` 中的权重卸载功能。在开发和调试时可跳过所有卸载/重载开销。
+- **默认值**：`False`（等价于 `"0"`）
+- **有效值**：`"1"`、`"true"`、`"yes"`（不区分大小写）表示禁用卸载；其他值保持默认行为
+- **用途**：设置后将完全绕过权重卸载
+
+```bash
+export AR_DISABLE_OFFLOAD=1
+```
+
+### AR_DISABLE_DATASET_SUBPROCESS
+- **描述**：禁用子进程方式进行数据集预处理。默认情况下，AutoRound 使用子进程确保所有临时内存在进程退出后被操作系统回收。
+- **默认值**：`False`
+- **有效值**：`"1"`、`"true"`（不区分大小写）表示禁用子进程；其他值表示启用子进程
+- **用途**：设置后数据集预处理将在主进程中运行
+
+```bash
+export AR_DISABLE_DATASET_SUBPROCESS=true
+```
+
+## 使用示例
+
+### 设置环境变量
+
+#### 通过 Shell 命令
+```bash
+# 将日志级别设置为 DEBUG
+export AR_LOG_LEVEL=DEBUG
+
+# 启用编译打包
+export AR_ENABLE_COMPILE_PACKING=1
+
+# 使用 ModelScope 下载模型
+export AR_USE_MODELSCOPE=true
+
+# 设置自定义工作目录
+export AR_WORK_SPACE=/tmp/autoround_workspace
+```
+
+#### 通过 Python 代码
+```python
+from auto_round.envs import set_config
+
+# 同时配置多个环境变量
+set_config(
+    AR_LOG_LEVEL="DEBUG",
+    AR_USE_MODELSCOPE=True,
+    AR_ENABLE_COMPILE_PACKING=True,
+    AR_WORK_SPACE="/tmp/autoround_workspace",
+)
+```
+
+### 查看环境变量
+
+#### 通过 Python 代码
+```python
+from auto_round import envs
+
+# 访问环境变量（懒加载求值）
+log_level = envs.AR_LOG_LEVEL
+use_modelscope = envs.AR_USE_MODELSCOPE
+enable_packing = envs.AR_ENABLE_COMPILE_PACKING
+workspace = envs.AR_WORK_SPACE
+
+print(f"日志级别: {log_level}")
+print(f"使用 ModelScope: {use_modelscope}")
+print(f"启用编译打包: {enable_packing}")
+print(f"工作目录: {workspace}")
+```
+
+#### 检查变量是否显式设置
+```python
+from auto_round.envs import is_set
+
+# 检查环境变量是否被显式设置
+if is_set("AR_LOG_LEVEL"):
+    print("AR_LOG_LEVEL 已被显式设置")
+else:
+    print("AR_LOG_LEVEL 正在使用默认值")
+```
+
+## 配置最佳实践
+
+1. **开发环境**：设置 `AR_LOG_LEVEL=TRACE` 或 `AR_LOG_LEVEL=DEBUG` 以获取详细日志
+2. **生产环境**：使用 `AR_LOG_LEVEL=WARNING` 或 `AR_LOG_LEVEL=ERROR` 减少日志噪声
+3. **中国用户**：建议设置 `AR_USE_MODELSCOPE=true` 以获得更好的模型下载速度
+4. **性能优化**：如有足够算力，可启用 `AR_ENABLE_COMPILE_PACKING=1`
+5. **自定义工作目录**：将 `AR_WORK_SPACE` 设置为磁盘空间充足的目录
+
+## 注意事项
+
+- 环境变量采用懒加载方式，仅在首次访问时读取
+- `set_config()` 函数提供了便捷的程序化多变量配置方式
+- `AR_USE_MODELSCOPE` 的布尔值会自动转换为适当的字符串表示
+- 所有环境变量名称区分大小写
+- 通过 `set_config()` 所做的修改将影响当前进程及其子进程