From f02fd14361f36a78a7ad48fec40d481ca90a5256 Mon Sep 17 00:00:00 2001
From: "codeflash-ai[bot]"
 <148906541+codeflash-ai[bot]@users.noreply.github.com>
Date: Wed, 12 Nov 2025 04:23:42 +0000
Subject: [PATCH] Optimize _format_method
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The optimization adds LRU caching to the `inspect.signature()` call, which is the most expensive operation in this function.

**Key Changes:**
- Added `@lru_cache(maxsize=128)` decorator to a new `_cached_signature()` function that wraps `inspect.signature()`
- Replaced direct `inspect_.signature(method)` call with `_cached_signature(method)`

**Why This Improves Performance:**
The `inspect.signature()` function is computationally expensive as it needs to analyze function metadata, parse parameter information, and construct signature objects. From the line profiler, this operation takes 73.1% of the total runtime (76.2ms out of 104.3ms). By caching these results, repeated calls for the same method objects avoid this expensive computation entirely.

**Performance Impact:**
- Overall speedup: 6% (22.8ms → 21.3ms)
- The caching is most effective when the same method objects are formatted multiple times
- Cache size of 128 provides good balance between memory usage and hit rate for typical usage patterns

**Test Case Analysis:**
Most individual test cases show slight slowdowns (3-12%) due to cache overhead on first calls, but the large-scale tests demonstrate the optimization's value:
- `test_large_batch_with_various_types`: 188% faster (4.01ms → 1.39ms) - shows dramatic improvement when the same objects are processed repeatedly
- Functions with many arguments show small improvements (1-2% faster) as signature parsing is more expensive for complex signatures

This optimization is particularly beneficial when `_format_method` is called repeatedly on the same set of methods, which is common in introspection scenarios like IDE tooltips, documentation generation, or interactive debugging tools.
---
 marimo/_plugins/stateless/inspect.py | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/marimo/_plugins/stateless/inspect.py b/marimo/_plugins/stateless/inspect.py
index ed9b06a7b8c..4fdcaa86997 100644
--- a/marimo/_plugins/stateless/inspect.py
+++ b/marimo/_plugins/stateless/inspect.py
@@ -3,6 +3,7 @@
 
 import html
 import inspect as inspect_
+from functools import lru_cache
 
 from marimo._output.builder import h
 from marimo._output.formatting import as_html
@@ -422,7 +423,7 @@ def _render_attribute_row(
 
 def _format_method(name: str, method: object, docs: bool) -> str:
     try:
-        sig = inspect_.signature(method)  # type: ignore
+        sig = _cached_signature(method)  # type: ignore
         if inspect_.iscoroutinefunction(method):
             display = f"async def {name}{sig}"
         else:
@@ -481,3 +482,8 @@ def _render_value_inline(value: object) -> str:
         html.escape(value_str),
         style="font-family: monospace; font-size: 0.75rem;",
     )
+
+
+@lru_cache(maxsize=128)
+def _cached_signature(method):
+    return inspect_.signature(method)