[Kernel] [Helion] [15/N] Split config files into per-platform files (#36698)

Signed-off-by: Yanan Cao <gmagogsfm@gmail.com>
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

tests/kernels/helion/test_config_manager.py

@@ -160,10 +160,11 @@ class TestConfigManager:
         """Test getting config file path for a kernel."""
         manager = ConfigManager(base_dir="/tmp")
 
-        file_path = manager.get_config_file_path("silu_mul_fp8")
+        dir_path = manager.get_config_file_path("silu_mul_fp8")
+        assert dir_path == Path("/tmp/silu_mul_fp8")
 
-        expected_path = Path("/tmp/silu_mul_fp8.json")
-        assert file_path == expected_path
+        file_path = manager.get_config_file_path("silu_mul_fp8", "nvidia_h100")
+        assert file_path == Path("/tmp/silu_mul_fp8/nvidia_h100.json")
 
     def test_ensure_base_dir_exists(self):
         """Test ensuring base directory exists."""
@@ -189,19 +190,19 @@ class TestConfigManager:
             assert config_set.get_platforms() == []
 
     def test_load_config_set_valid_file(self):
-        """Test loading config set from valid file."""
+        """Test loading config set from per-platform files."""
         with tempfile.TemporaryDirectory() as temp_dir:
-            # Use realistic config data
             kernel_config = {
                 "block_sizes": [128, 64],
                 "num_warps": 8,
                 "num_stages": 6,
                 "pid_type": "persistent_interleaved",
             }
-            config_data = {"h100": {"batch_32_hidden_4096": kernel_config}}
-            config_file = Path(temp_dir) / "test_kernel.json"
-            with open(config_file, "w") as f:
-                json.dump(config_data, f)
+            kernel_dir = Path(temp_dir) / "test_kernel"
+            kernel_dir.mkdir()
+            platform_file = kernel_dir / "h100.json"
+            with open(platform_file, "w") as f:
+                json.dump({"batch_32_hidden_4096": kernel_config}, f)
 
             manager = ConfigManager(base_dir=temp_dir)
             config_set = manager.load_config_set("test_kernel")
@@ -210,7 +211,6 @@ class TestConfigManager:
             assert config_set.kernel_name == "test_kernel"
             assert config_set.get_platforms() == ["h100"]
 
-            # Verify the config was loaded correctly
             config = config_set.get_config("h100", "batch_32_hidden_4096")
             assert isinstance(config, helion.Config)
             assert config.block_sizes == [128, 64]
@@ -219,7 +219,9 @@ class TestConfigManager:
     def test_load_config_set_invalid_json(self):
         """Test loading config set from file with invalid JSON."""
         with tempfile.TemporaryDirectory() as temp_dir:
-            config_file = Path(temp_dir) / "test_kernel.json"
+            kernel_dir = Path(temp_dir) / "test_kernel"
+            kernel_dir.mkdir()
+            config_file = kernel_dir / "h100.json"
             with open(config_file, "w") as f:
                 f.write("invalid json content {")
 
@@ -231,9 +233,8 @@ class TestConfigManager:
             assert config_set.get_platforms() == []
 
     def test_save_config_set(self):
-        """Test saving ConfigSet to file."""
+        """Test saving ConfigSet to per-platform files."""
         with tempfile.TemporaryDirectory() as temp_dir:
-            # Use realistic config data
             kernel_config = {
                 "block_sizes": [256, 128],
                 "num_warps": 16,
@@ -246,31 +247,34 @@ class TestConfigManager:
             manager = ConfigManager(base_dir=temp_dir)
             saved_path = manager.save_config_set(config_set)
 
-            expected_path = Path(temp_dir) / "test_kernel.json"
-            assert saved_path == expected_path
-            assert saved_path.exists()
+            expected_dir = Path(temp_dir) / "test_kernel"
+            assert saved_path == expected_dir
+            assert saved_path.is_dir()
 
-            with open(saved_path) as f:
+            platform_file = expected_dir / "h100.json"
+            assert platform_file.exists()
+            with open(platform_file) as f:
                 loaded_data = json.load(f)
-            assert loaded_data == data
+            assert loaded_data == data["h100"]
 
     def test_save_config_set_creates_directory(self):
         """Test that save_config_set creates parent directories if needed."""
         with tempfile.TemporaryDirectory() as temp_dir:
             nested_dir = Path(temp_dir) / "nested" / "configs"
-            config_set = ConfigSet("test_kernel")
+            data = {"h100": {"default": {"num_warps": 4}}}
+            config_set = ConfigSet.from_dict("test_kernel", data)
 
             manager = ConfigManager(base_dir=nested_dir)
             saved_path = manager.save_config_set(config_set)
 
             assert nested_dir.exists()
             assert nested_dir.is_dir()
-            assert saved_path.exists()
+            assert saved_path.is_dir()
+            assert (saved_path / "h100.json").exists()
 
     def test_get_platform_configs(self):
         """Test getting all configs for a specific platform."""
         with tempfile.TemporaryDirectory() as temp_dir:
-            # Use realistic config data
             config_1 = {"num_warps": 4, "num_stages": 3, "block_sizes": [64, 32]}
             config_2 = {"num_warps": 8, "num_stages": 5, "block_sizes": [128, 64]}
             default_config = {
@@ -280,17 +284,19 @@ class TestConfigManager:
             }
             config_3 = {"num_warps": 2, "num_stages": 2, "block_sizes": [32, 16]}
 
-            config_data = {
-                "h100": {
-                    "batch_32_hidden_4096": config_1,
-                    "batch_64_hidden_2048": config_2,
-                    "default": default_config,
-                },
-                "a100": {"batch_16_hidden_1024": config_3},
-            }
-            config_file = Path(temp_dir) / "test_kernel.json"
-            with open(config_file, "w") as f:
-                json.dump(config_data, f)
+            kernel_dir = Path(temp_dir) / "test_kernel"
+            kernel_dir.mkdir()
+            with open(kernel_dir / "h100.json", "w") as f:
+                json.dump(
+                    {
+                        "batch_32_hidden_4096": config_1,
+                        "batch_64_hidden_2048": config_2,
+                        "default": default_config,
+                    },
+                    f,
+                )
+            with open(kernel_dir / "a100.json", "w") as f:
+                json.dump({"batch_16_hidden_1024": config_3}, f)
 
             manager = ConfigManager(base_dir=temp_dir)
 
@@ -302,7 +308,6 @@ class TestConfigManager:
             for config in h100_configs.values():
                 assert isinstance(config, helion.Config)
 
-            # Verify specific config details
             assert h100_configs["batch_32_hidden_4096"].num_warps == 4
             assert h100_configs["default"].num_stages == 7
 

vllm/kernels/helion/config_manager.py

@@ -8,23 +8,15 @@ operations, including naming conventions, directory resolution, and file I/O.
 
 Config File Structure
 ---------------------
-Each kernel has a single JSON config file: {kernel_name}.json
-
-The file uses a simplified 2-layer hierarchical structure:
-{
-    "h100": {                             # GPU platform
-        "default": { ... },               # Fallback configuration
-        "batch_32_hidden_4096": { ... },
-        "batch_64_hidden_8192": { ... }
-    },
-    "a100": {
-        "default": { ... },
-        "batch_16_hidden_2048": { ... }
-    }
-}
-
-Example file: silu_mul_fp8.json
+Each kernel has a directory: {kernel_name}/
+Inside, each GPU platform has its own JSON file: {kernel_name}/{platform}.json
 
+For example:
+    silu_mul_fp8/
+        nvidia_h100.json    # { "default": {...}, "batch_32_hidden_4096": {...} }
+        nvidia_h200.json    # { "batch_16_hidden_2048": {...} }
+
+Each platform file maps config keys to Helion config objects.
 Config keys should be structured strings that encode the relevant
 parameters (e.g., "batch_32_hidden_4096", "seq_512_heads_16", "fp8_batch_64", etc.).
 
@@ -212,8 +204,15 @@ class ConfigManager:
         cls._instance = None
         cls._instance_base_dir = None
 
-    def get_config_file_path(self, kernel_name: str) -> Path:
-        return self._base_dir / f"{kernel_name}.json"
+    def get_kernel_dir(self, kernel_name: str) -> Path:
+        return self._base_dir / kernel_name
+
+    def get_config_file_path(
+        self, kernel_name: str, platform: str | None = None
+    ) -> Path:
+        if platform is not None:
+            return self.get_kernel_dir(kernel_name) / f"{platform}.json"
+        return self.get_kernel_dir(kernel_name)
 
     def ensure_base_dir_exists(self) -> Path:
         self._base_dir.mkdir(parents=True, exist_ok=True)
@@ -230,39 +229,59 @@ class ConfigManager:
                 f"Config directory '{self._base_dir}' is not writable: {e}"
             ) from e
 
-    def load_config_set(self, kernel_name: str) -> ConfigSet:
-        config_path = self.get_config_file_path(kernel_name)
+    def _load_platform_file(self, kernel_name: str, platform: str) -> dict[str, Any]:
+        config_path = self.get_config_file_path(kernel_name, platform)
         if not config_path.exists():
-            return ConfigSet.from_dict(kernel_name, {})
-
+            return {}
         try:
             with open(config_path) as f:
-                data = json.load(f)
-            return ConfigSet.from_dict(kernel_name, data)
+                return json.load(f)
         except (json.JSONDecodeError, OSError) as e:
             logger.error("Failed to load config file %s: %s", config_path, e)
+            return {}
+
+    def load_config_set(self, kernel_name: str) -> ConfigSet:
+        kernel_dir = self.get_kernel_dir(kernel_name)
+        if not kernel_dir.is_dir():
             return ConfigSet.from_dict(kernel_name, {})
 
+        data: dict[str, Any] = {}
+        for platform_file in sorted(kernel_dir.glob("*.json")):
+            platform = platform_file.stem
+            try:
+                with open(platform_file) as f:
+                    platform_data = json.load(f)
+                data[platform] = platform_data
+            except (json.JSONDecodeError, OSError) as e:
+                logger.error("Failed to load config file %s: %s", platform_file, e)
+
+        return ConfigSet.from_dict(kernel_name, data)
+
     def get_platform_configs(
         self, kernel_name: str, platform: str
     ) -> dict[str, helion.Config]:
-        config_set = self.load_config_set(kernel_name)
+        platform_data = self._load_platform_file(kernel_name, platform)
+        if not platform_data:
+            return {}
+        config_set = ConfigSet.from_dict(kernel_name, {platform: platform_data})
         config_keys = config_set.get_config_keys(platform)
-
         return {
             config_key: config_set.get_config(platform, config_key)
             for config_key in config_keys
         }
 
     def save_config_set(self, config_set: ConfigSet) -> Path:
-        config_path = self.get_config_file_path(config_set.kernel_name)
-        config_path.parent.mkdir(parents=True, exist_ok=True)
+        kernel_dir = self.get_kernel_dir(config_set.kernel_name)
+        kernel_dir.mkdir(parents=True, exist_ok=True)
 
-        with open(config_path, "w") as f:
-            json.dump(config_set.to_dict(), f, indent=2)
+        full_data = config_set.to_dict()
+        for platform, platform_data in full_data.items():
+            platform_path = kernel_dir / f"{platform}.json"
+            with open(platform_path, "w") as f:
+                json.dump(platform_data, f, indent=2)
+            logger.info("Saved config to: %s", platform_path)
 
-        logger.info("Saved config to: %s", config_path)
-        return config_path
+        return kernel_dir
 
     def save_configs(
         self,
@@ -271,11 +290,18 @@ class ConfigManager:
         configs: dict[str, "helion.Config"],
     ) -> Path:
         """Save configs for a kernel/platform, merging with existing."""
-        config_set = self.load_config_set(kernel_name)
+        platform_data = self._load_platform_file(kernel_name, platform)
         for config_key, config in configs.items():
-            config_set.set_config(platform, config_key, config)
-        return self.save_config_set(config_set)
+            platform_data[config_key] = json.loads(config.to_json())
+
+        platform_path = self.get_config_file_path(kernel_name, platform)
+        platform_path.parent.mkdir(parents=True, exist_ok=True)
+        with open(platform_path, "w") as f:
+            json.dump(platform_data, f, indent=2)
+
+        logger.info("Saved config to: %s", platform_path)
+        return platform_path
 
     def config_exists(self, kernel_name: str, platform: str, config_key: str) -> bool:
-        config_set = self.load_config_set(kernel_name)
-        return config_set.has_config(platform, config_key)
+        platform_data = self._load_platform_file(kernel_name, platform)
+        return config_key in platform_data