diff --git a/xtuner/_lite/datasets/cache.py b/xtuner/_lite/datasets/cache.py
index 9de84eab7..a46ef47ce 100644
--- a/xtuner/_lite/datasets/cache.py
+++ b/xtuner/_lite/datasets/cache.py
@@ -1,5 +1,6 @@
 # Copyright (c) OpenMMLab. All rights reserved.
 import hashlib
+import os
 import tempfile
 from abc import ABC, abstractmethod
 from pathlib import Path
@@ -7,6 +8,8 @@
 
 from transformers import PreTrainedTokenizer
 
+from xtuner._lite import get_logger
+
 
 class CacheObj(TypedDict, total=False):
     num_tokens: int
@@ -23,8 +26,15 @@ def hash(self) -> str:
 
 
 def calculate_file_sha256(path):
+    hash_method = os.environ.get("HASH_METHOD", "sha256")
+    assert (
+        hash_method in hashlib.algorithms_guaranteed
+    ), f"hash method {hash_method} not supported"
+    if hash_method != "sha256":
+        get_logger().warning(f"Non-default hash method {hash_method} is used")
+    hash_method = getattr(hashlib, hash_method)
     with open(path, "rb") as f:
-        file_hash = hashlib.sha256()
+        file_hash = hash_method()
         file_hash.update(f.read())
     return file_hash.hexdigest()
 
diff --git a/xtuner/_lite/datasets/jsonl.py b/xtuner/_lite/datasets/jsonl.py
index 1e96e5114..52f78fa95 100644
--- a/xtuner/_lite/datasets/jsonl.py
+++ b/xtuner/_lite/datasets/jsonl.py
@@ -8,6 +8,7 @@
 import signal
 import sys
 from concurrent.futures import ProcessPoolExecutor
+from functools import partial
 from typing import Any, Callable
 
 import numpy as np
@@ -137,11 +138,14 @@ def count_offsets(self, cache_dir=None):
 
         return offsets
 
-    def _tokenize_by_offset(self, offset):
+    def _tokenize_by_offset(self, offset, only_num_tokens=False):
         with open(self.path) as f:
             f.seek(offset)
             data = json.loads(f.readline())
-        return self.tokenize_fn(data)
+        tokenize = self.tokenize_fn(data)
+        if only_num_tokens:
+            tokenize = {"num_tokens": tokenize["num_tokens"]}
+        return tokenize
 
     def count_tokens(self, offsets, cache_dir=None):
         num_samples = len(offsets)
@@ -169,7 +173,9 @@ def count_tokens(self, offsets, cache_dir=None):
             tokenized = list(
                 tqdm(
                     executor.map(
-                        self._tokenize_by_offset, offsets_shard, chunksize=chunk_size
+                        partial(self._tokenize_by_offset, only_num_tokens=True),
+                        offsets_shard,
+                        chunksize=chunk_size,
                     ),
                     desc=desc,
                     total=len(offsets_shard),