Skip UVM-heavy PatternGen seeds test under compute-sanitizer

Add cuda_python_test_helpers.under_compute_sanitizer() and use it to skip the
slow patterngen seed test under sanitizer runs. Document the env-var coupling
in ci/tools/env-vars.

Author: Andy-Jost

ci/tools/env-vars

@@ -68,6 +68,9 @@ elif [[ "${1}" == "test" ]]; then
   # We don't test compute-sanitizer on CTK<12 because backporting fixes is too much effort
   # We only test compute-sanitizer on python 3.12 arbitrarily; we don't need to use sanitizer on the entire matrix
   # Only local ctk installs have compute-sanitizer; there is no wheel for it
+  # NOTE: If you change sanitizer-related env vars here (e.g., SETUP_SANITIZER,
+  # SANITIZER_CMD, CUDA_INJECTION64_PATH), update
+  # cuda_python_test_helpers.under_compute_sanitizer() accordingly.
   if [[ "${PY_VER}" == "3.12" && "${CUDA_VER}" != "11.8.0" && "${LOCAL_CTK}" == 1 && "${HOST_PLATFORM}" == linux* ]]; then
     echo "LATEST_CUDA_VERSION=$(bash .github/workflows/guess_latest.sh $TEST_CUDA_MAJOR)" >> $GITHUB_ENV
     SETUP_SANITIZER=1

cuda_core/tests/test_helpers.py

@@ -11,6 +11,8 @@
 from helpers.latch import LatchKernel
 from helpers.logging import TimestampedLogger
 
+from cuda_python_test_helpers import under_compute_sanitizer
+
 ENABLE_LOGGING = False  # Set True for test debugging and development
 NBYTES = 64
 
@@ -66,6 +68,10 @@ def test_01():
     pass
 
 
+@pytest.mark.skipif(
+    under_compute_sanitizer(),
+    reason="Too slow under compute-sanitizer (UVM-heavy test).",
+)
 def test_patterngen_seeds():
     """Test PatternGen with seed argument."""
     device = Device()

cuda_python_test_helpers/cuda_python_test_helpers/__init__.py

@@ -16,6 +16,7 @@
     "IS_WSL",
     "libc",
     "supports_ipc_mempool",
+    "under_compute_sanitizer",
 ]
 
 
@@ -37,6 +38,38 @@ def _detect_wsl() -> bool:
     libc = ctypes.CDLL("libc.so.6")
 
 
+def under_compute_sanitizer() -> bool:
+    """Return True if the current process is likely running under compute-sanitizer.
+
+    This is best-effort and primarily intended for CI, where the environment
+    is configured by wrapper scripts.
+    """
+    # Explicit override (if we ever want to set this directly in CI).
+    if os.environ.get("CUDA_PYTHON_UNDER_SANITIZER") == "1":
+        return True
+
+    # CI sets these when compute-sanitizer is enabled.
+    if os.environ.get("SETUP_SANITIZER") == "1":
+        return True
+
+    cmd = os.environ.get("SANITIZER_CMD", "")
+    if "compute-sanitizer" in cmd or "cuda-memcheck" in cmd:
+        return True
+
+    # Secondary signals: depending on how tests are invoked, the wrapper name may
+    # appear in argv (e.g. `compute-sanitizer pytest ...`). This is not reliable
+    # in general (often argv0 is `python`/`pytest`), but it's cheap and harmless.
+    argv0 = os.path.basename(sys.argv[0]) if sys.argv else ""
+    if argv0 in ("compute-sanitizer", "cuda-memcheck"):
+        return True
+    if any(("compute-sanitizer" in a or "cuda-memcheck" in a) for a in sys.argv):
+        return True
+
+    # Another common indicator: sanitizer injectors are configured via env vars.
+    inj = os.environ.get("CUDA_INJECTION64_PATH", "")
+    return "compute-sanitizer" in inj or "cuda-memcheck" in inj
+
+
 @functools.cache
 def supports_ipc_mempool(device_id: Union[int, object]) -> bool:
     """Return True if mempool IPC via POSIX file descriptor is supported.