修正: cpu_num_threadsが未指定または0の場合に、論理コア数の半分をコアに渡すようにする

test/test_core_utility.py

@@ -0,0 +1,18 @@
+from unittest import TestCase
+from unittest.mock import patch
+
+from voicevox_engine.utility.core_utility import get_half_logical_cores
+
+
+class TestHalfLogicalCores(TestCase):
+    @patch("os.cpu_count", return_value=8)
+    def test_half_logical_cores_even(self, mock_cpu_count):
+        self.assertEqual(get_half_logical_cores(), 4)
+
+    @patch("os.cpu_count", return_value=9)
+    def test_half_logical_cores_odd(self, mock_cpu_count):
+        self.assertEqual(get_half_logical_cores(), 4)
+
+    @patch("os.cpu_count", return_value=None)
+    def test_half_logical_cores_none(self, mock_cpu_count):
+        self.assertEqual(get_half_logical_cores(), 0)

voicevox_engine/core/core_initializer.py

@@ -4,6 +4,7 @@
 from typing import List, Optional
 
 from ..tts_pipeline.tts_engine import CoreAdapter
+from ..utility.core_utility import get_half_logical_cores
 from ..utility.path_utility import engine_root, get_save_dir
 from .core_wrapper import CoreWrapper, load_runtime_lib
 
@@ -44,10 +45,10 @@ def initialize_cores(
     if cpu_num_threads == 0 or cpu_num_threads is None:
         print(
             "Warning: cpu_num_threads is set to 0. "
-            + "( The library leaves the decision to the synthesis runtime )",
+            + "Setting it to half of the logical cores.",
             file=sys.stderr,
         )
-        cpu_num_threads = 0
+        cpu_num_threads = get_half_logical_cores()
 
     # ディレクトリを設定する
     # 引数による指定を反映する

voicevox_engine/utility/core_utility.py

@@ -0,0 +1,8 @@
+import os
+
+
+def get_half_logical_cores() -> int:
+    logical_cores = os.cpu_count()
+    if logical_cores is None:
+        return 0
+    return logical_cores // 2