feat: add profiler util (#5601)

* feat(config): add profiling config settings

- `profile_graphs` enables graph profiling with cProfile
- `profiles_dir` sets the output for profiles

* feat(nodes): add Profiler util

Simple wrapper around cProfile.

* feat(nodes): use Profiler in invocation processor

* scripts: add generate_profile_graphs.sh script

Helper to generate graphs for profiles.

* pkg: add snakeviz and gprof2dot to dev deps

These are useful for profiling.

* tests: add tests for profiler util

* fix(profiler): handle previous profile not stopped cleanly

* feat(profiler): add profile_prefix config setting

The prefix is used when writing profile output files. Useful to organise profiles into sessions.

* tidy(profiler): add `_` to private API

* feat(profiler): simplify API

* feat(profiler): use child logger for profiler logs

* chore(profiler): update docstrings

* feat(profiler): stop() returns output path

* chore(profiler): fix docstring

* tests(profiler): update tests

* chore: ruff

tests/test_profiler.py

@@ -0,0 +1,53 @@
+import re
+from logging import Logger
+from pathlib import Path
+from tempfile import TemporaryDirectory
+
+import pytest
+
+from invokeai.app.util.profiler import Profiler
+
+
+def test_profiler_starts():
+    with TemporaryDirectory() as tempdir:
+        profiler = Profiler(logger=Logger("test_profiler"), output_dir=Path(tempdir))
+        assert not profiler._profiler
+        assert not profiler.profile_id
+        profiler.start("test")
+        assert profiler._profiler
+        assert profiler.profile_id == "test"
+        profiler.stop()
+        assert not profiler._profiler
+        assert not profiler.profile_id
+        profiler.start("test2")
+        assert profiler._profiler
+        assert profiler.profile_id == "test2"
+        profiler.stop()
+
+
+def test_profiler_profiles():
+    with TemporaryDirectory() as tempdir:
+        profiler = Profiler(logger=Logger("test_profiler"), output_dir=Path(tempdir))
+        profiler.start("test")
+        for _ in range(1000000):
+            pass
+        profiler.stop()
+        assert (Path(tempdir) / "test.prof").exists()
+
+
+def test_profiler_profiles_with_prefix():
+    with TemporaryDirectory() as tempdir:
+        profiler = Profiler(logger=Logger("test_profiler"), output_dir=Path(tempdir), prefix="prefix")
+        profiler.start("test")
+        for _ in range(1000000):
+            pass
+        profiler.stop()
+        assert (Path(tempdir) / "prefix_test.prof").exists()
+
+
+def test_profile_fails_if_not_set_up():
+    with TemporaryDirectory() as tempdir:
+        profiler = Profiler(logger=Logger("test_profiler"), output_dir=Path(tempdir))
+        match = re.escape("Profiler not initialized. Call start() first.")
+        with pytest.raises(RuntimeError, match=match):
+            profiler.stop()