[test stats] use published test stats for sharding (#81116)

Use the nightly-published test stats to perform sharding, instead of
calculating it in every build job.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/81116
Approved by: https://github.com/janeyx99

.github/workflows/_linux-build.yml

@@ -135,7 +135,7 @@ jobs:
       - name: Archive artifacts into zip
         if: inputs.build-generates-artifacts
         run: |
-          zip -1 -r artifacts.zip dist/ build/custom_test_artifacts build/lib build/bin .pytorch-test-times.json
+          zip -1 -r artifacts.zip dist/ build/custom_test_artifacts build/lib build/bin
 
       - name: Store PyTorch Build Artifacts on S3
         uses: seemethere/upload-artifact-s3@v5

.jenkins/pytorch/build.sh

@@ -296,10 +296,4 @@ else
   fi
 fi
 
-if [[ "$BUILD_ENVIRONMENT" != *libtorch* && "$BUILD_ENVIRONMENT" != *bazel* ]]; then
-  # export test times so that potential sharded tests that'll branch off this build will use consistent data
-  # don't do this for libtorch as libtorch is C++ only and thus won't have python tests run on its build
-  python test/run_test.py --export-past-test-times
-fi
-
 print_sccache_stats

.jenkins/pytorch/win-test-helpers/build_pytorch.bat

@@ -146,9 +146,6 @@ python setup.py install --cmake && sccache --show-stats && (
     if errorlevel 1 exit /b
     if not errorlevel 0 exit /b
 
-    :: export test times so that potential sharded tests that'll branch off this build will use consistent data
-    python test/run_test.py --export-past-test-times %PYTORCH_FINAL_PACKAGE_DIR%/.pytorch-test-times.json
-
     :: Also save build/.ninja_log as an artifact
     copy /Y "build\.ninja_log" "%PYTORCH_FINAL_PACKAGE_DIR%\"
   )

.jenkins/pytorch/win-test-helpers/test_python_jit_legacy.bat

@@ -1,7 +1,6 @@
 call %SCRIPT_HELPERS_DIR%\setup_pytorch_env.bat
 
 echo Copying over test times file
-copy /Y "%PYTORCH_FINAL_PACKAGE_DIR_WIN%\.pytorch-test-times.json" "%TEST_DIR_WIN%"
 
 pushd test
 

.jenkins/pytorch/win-test-helpers/test_python_shard.bat

@@ -21,9 +21,6 @@ if "%SHARD_NUMBER%" == "1" (
   )
 )
 
-echo Copying over test times file
-copy /Y "%PYTORCH_FINAL_PACKAGE_DIR_WIN%\.pytorch-test-times.json" "%TEST_DIR_WIN%"
-
 echo Run nn tests
 python run_test.py --exclude-jit-executor --exclude-distributed-tests --shard "%SHARD_NUMBER%" "%NUM_TEST_SHARDS%" --verbose
 if ERRORLEVEL 1 goto fail

test/run_test.py

@@ -32,11 +32,11 @@ REPO_ROOT = pathlib.Path(__file__).resolve().parent.parent
 try:
     # using tools/ to optimize test run.
     sys.path.append(str(REPO_ROOT))
+    from tools.stats.import_test_stats import get_test_times
     from tools.testing.test_selections import (
-        export_S3_test_times,
-        get_shard_based_on_S3,
         get_reordered_tests,
         get_test_case_configs,
+        calculate_shards,
     )
     HAVE_TEST_SELECTION_TOOLS = True
 except ImportError:
@@ -677,13 +677,6 @@ def parse_args():
         help="additional arguments passed through to unittest, e.g., "
         "python run_test.py -i sparse -- TestSparse.test_factory_size_check",
     )
-    parser.add_argument(
-        "--export-past-test-times",
-        nargs="?",
-        type=str,
-        const=TEST_TIMES_FILE,
-        help="dumps test times from previous S3 stats into a file, format JSON",
-    )
     parser.add_argument(
         "--shard",
         nargs=2,
@@ -838,11 +831,21 @@ def get_selected_tests(options):
         assert num_shards <= len(
             selected_tests
         ), f"Number of shards must be less than {len(selected_tests)}"
-        # TODO: fix this to use test_times_filename, but currently this is not working
-        # because setting the export arg immeidately halts the test execution.
-        selected_tests = get_shard_based_on_S3(
-            which_shard, num_shards, selected_tests, TEST_TIMES_FILE
+
+        if num_shards == 1:
+            return selected_tests
+
+        # Download previous test times to make sharding decisions
+        test_file_times = get_test_times(str(REPO_ROOT), filename=TEST_TIMES_FILE)
+        if len(test_file_times) == 0:
+            print(
+                "::warning:: Gathered no stats from S3. Proceeding with default sharding plan."
             )
+            selected_tests = selected_tests[which_shard - 1 :: num_shards]
+        else:
+            shards = calculate_shards(num_shards, selected_tests, test_file_times)
+            _, tests_from_shard = shards[which_shard - 1]
+            selected_tests = tests_from_shard
 
     # skip all distributed tests if distributed package is not available.
     if not dist.is_available():
@@ -882,15 +885,6 @@ def run_test_module(test: str, test_directory: str, options) -> Optional[str]:
 def main():
     options = parse_args()
 
-    # TODO: move this export & download function in tools/ folder
-    test_times_filename = options.export_past_test_times
-    if test_times_filename:
-        print(
-            f"Exporting past test times from S3 to {test_times_filename}, no tests will be run."
-        )
-        export_S3_test_times(test_times_filename)
-        return
-
     test_directory = str(REPO_ROOT / "test")
     selected_tests = get_selected_tests(options)
 

tools/stats/import_test_stats.py

@@ -41,6 +41,7 @@ def fetch_and_cache(
     This fetch and cache utils allows sharing between different process.
     """
     path = os.path.join(dirpath, name)
+    print(f"Downloading {url} to {path}")
 
     def is_cached_file_valid() -> bool:
         # Check if the file is new enough (see: FILE_CACHE_LIFESPAN_SECONDS). A real check
@@ -80,6 +81,21 @@ def get_slow_tests(
         return {}
 
 
+def get_test_times(dirpath: str, filename: str) -> Dict[str, float]:
+    url = "https://raw.githubusercontent.com/pytorch/test-infra/generated-stats/stats/test-times.json"
+
+    def process_response(the_response: Dict[str, Any]) -> Any:
+        build_environment = os.environ["BUILD_ENVIRONMENT"]
+        test_config = os.environ["TEST_CONFIG"]
+        return the_response[build_environment][test_config]
+
+    try:
+        return fetch_and_cache(dirpath, filename, url, process_response)
+    except Exception:
+        print("Couldn't download test times...")
+        return {}
+
+
 def get_disabled_tests(
     dirpath: str, filename: str = DISABLED_TESTS_FILE
 ) -> Optional[Dict[str, Any]]: