Use Modal async API to remove executor concurrency bottleneck

src/libkernelbot/launchers/modal.py

@@ -20,7 +20,6 @@ def __init__(self, add_include_dirs: list):
     async def run_submission(
         self, config: dict, gpu_type: GPU, status: RunProgressReporter
     ) -> FullResult:
-        loop = asyncio.get_event_loop()
         if config["lang"] == "cu":
             config["include_dirs"] = config.get("include_dirs", []) + self.additional_include_dirs
         func_name = self._function_name(config, gpu_type)
@@ -29,10 +28,8 @@ async def run_submission(
 
         await status.push("⏳ Waiting for Modal run to finish...")
 
-        result = await loop.run_in_executor(
-            None,
-            lambda: modal.Function.from_name("discord-bot-runner", func_name).remote(config=config),
-        )
+        function = modal.Function.from_name("discord-bot-runner", func_name)
+        result = await function.remote.aio(config=config)
 
         await status.update("✅ Waiting for modal run to finish... Done")
 

tests/test_modal.py

@@ -4,7 +4,7 @@
 from pathlib import Path
 from types import SimpleNamespace
 from typing import Tuple
-from unittest.mock import MagicMock, patch
+from unittest.mock import AsyncMock, MagicMock, patch
 
 import pytest
 
@@ -29,6 +29,26 @@ async def update(self, message: str):
         self.updates.append(message)
 
 
+@pytest.mark.asyncio
+async def test_modal_submission_uses_native_async_api():
+    launcher = ModalLauncher(add_include_dirs=["/extra/include"])
+    reporter = MockProgressReporter()
+    function = MagicMock()
+    expected = object()
+    function.remote.aio = AsyncMock(return_value=expected)
+    config = {"lang": "cu"}
+
+    with patch("libkernelbot.launchers.modal.modal.Function.from_name", return_value=function):
+        result = await launcher.run_submission(config, get_gpu_by_name("B200"), reporter)
+
+    assert result is expected
+    assert config["include_dirs"] == ["/extra/include"]
+    function.remote.aio.assert_awaited_once_with(config=config)
+    function.remote.assert_not_called()
+    assert reporter.messages == ["⏳ Waiting for Modal run to finish..."]
+    assert reporter.updates == ["✅ Waiting for modal run to finish... Done"]
+
+
 @pytest.mark.asyncio
 async def test_modal_queue_status_uses_function_stats():
     launcher = ModalLauncher(add_include_dirs=[])