Fix multiprocessing.Process tests not collected by coverage and gcov (

#486) * Fix `multiprocessing.Process` tests not collected by coverage and gcov * fix --concurrency=multiprocessing
DeepLink-org · Dec 4, 2023 · 2a3b0c8 · 2a3b0c8
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Showing 5 changed files with 27 additions and 4 deletions.
diff --git a/dipu/tests/python/README.md b/dipu/tests/python/README.md
@@ -49,3 +49,15 @@
 如果需要自动化检测 C++ 库内部的输出，可以使用 `test.python.utils.stdout_redirector.stdout_redirector` 来捕获。
 
 独立测例可以包含 print。不过，在自动生成的单元测试中，独立测例中的输出会在测试通过的情况下被消除。
+
+#### 子进程的 coverage 收集
+
+使用 `multiprocessing.Process` 创建的子进程在 CI 上跑 coverage 时不会被统计，因此使用这种测试方式（e.g. `test_allocator.py`）的独立测例需要一些特别的处理。
+
+#### C++ `gcov`
+
+在调用 `multiprocessing.Process` 之前，**必须**调用 `multiprocessing.set_start_method('spawn', force=True)` 修改 multiprocessing 的默认进程生成方式。
+
+##### Python `coverage`
+
+代码**无需**额外修改，而是需要在 coverage run 中加入额外的 flag。目前在 `run_tests.sh` 中已经配置好了。
diff --git a/dipu/tests/python/individual_scripts/test_allocator.py b/dipu/tests/python/individual_scripts/test_allocator.py
@@ -1,5 +1,5 @@
 import os
-from multiprocessing import Process
+from multiprocessing import Process, set_start_method
 
 
 def test_allocator(max_allocate, step, algorithm, log_mask, test_pin_memory=True):
@@ -67,6 +67,7 @@ def test_allocator(max_allocate, step, algorithm, log_mask, test_pin_memory=True
 
 
 if __name__ == "__main__":
+    set_start_method('spawn', force=True)
     max_allocate = 1 << 15
     p1 = Process(
         target=test_allocator,

diff --git a/dipu/tests/python/individual_scripts/test_dipu_op_register.py b/dipu/tests/python/individual_scripts/test_dipu_op_register.py
@@ -1,5 +1,5 @@
 # Copyright (c) 2023, DeepLink.
-from multiprocessing import Process
+from multiprocessing import Process, set_start_method
 from tests.python.utils.local_eviron import local_eviron
 
 
@@ -15,6 +15,7 @@ def _test_op_register(mode):
 
 
 if __name__ == "__main__":
+    set_start_method('spawn', force=True)
     p1 = Process(
         target=_test_op_register,
         args=(0,),

diff --git a/dipu/tests/python/individual_scripts/test_memory_stats.py b/dipu/tests/python/individual_scripts/test_memory_stats.py
@@ -1,5 +1,5 @@
 import os
-from multiprocessing import Process
+from multiprocessing import Process, set_start_method
 
 
 def test_mem_stats(algorithm, log_mask):
@@ -61,6 +61,7 @@ def test_mem_stats(algorithm, log_mask):
 
 
 if __name__ == "__main__":
+    set_start_method('spawn', force=True)
     p1 = Process(
         target=test_mem_stats,
         args=("BF", 0),

diff --git a/dipu/tests/python/run_tests.sh b/dipu/tests/python/run_tests.sh
@@ -2,7 +2,15 @@
 
 function run_coverage {
   if [ "$USE_COVERAGE" == "ON" ]; then
-    coverage run --source="$TORCH_DIPU_DIR" -p "$@"
+    # We need to add "--concurrency=multiprocessing" to collect coverage data from
+    # `multiprocessing.Process`. This flag requires all other configurations in
+    # `.coveragerc`.
+    cat << EOF > .coveragerc
+[run]
+  source = ${TORCH_DIPU_DIR}
+  parallel = True
+EOF
+    coverage run --concurrency=multiprocessing "$@"
   else
     python "$@"
   fi