perf(hooks): bind callgrind start/stop directly to avoid extra frame

Assign callgrind_start_instrumentation and callgrind_stop_instrumentation
as instance attributes pointing straight at the native C functions
instead of routing through Python wrapper methods. This removes one
Python stack frame from the hot path around instrumented code, which
matters because Valgrind/callgrind measurements include every frame
that's live while instrumentation is on.

Co-Authored-By: Claude <noreply@anthropic.com>

Author: art049

src/pytest_codspeed/instruments/hooks/__init__.py

@@ -11,7 +11,7 @@
 from pytest_codspeed.utils import SUPPORTS_PERF_TRAMPOLINE
 
 if TYPE_CHECKING:
- from typing import Any
+ from typing import Any, Callable
 
 # Feature flags for instrument hooks
 FEATURE_DISABLE_CALLGRIND_MARKERS = 0
@@ -22,6 +22,10 @@ class InstrumentHooks:
 
  _module: Any
  _instance: Any
+ # Bound directly to the C functions in __init__ to avoid an extra Python
+ # stack frame when starting/stopping callgrind instrumentation.
+ callgrind_start_instrumentation: Callable[[], None]
+ callgrind_stop_instrumentation: Callable[[], None]
 
  def __init__(self) -> None:
  if os.environ.get("CODSPEED_ENV") is None:
@@ -35,6 +39,12 @@ def __init__(self) -> None:
  except ImportError as e:
  raise RuntimeError(f"Failed to load instrument hooks library: {e}") from e
  self._module = dist_instrument_hooks
+ self.callgrind_start_instrumentation = (
+ dist_instrument_hooks.callgrind_start_instrumentation
+        )
+ self.callgrind_stop_instrumentation = (
+ dist_instrument_hooks.callgrind_stop_instrumentation
+        )
 
  self._instance = self._module.instrument_hooks_init()
  if self._instance is None:
@@ -87,14 +97,6 @@ def is_instrumented(self) -> bool:
  """Check if simulation is active."""
  return self._module.instrument_hooks_is_instrumented(self._instance)
 
- def callgrind_start_instrumentation(self) -> None:
- """Start callgrind instrumentation."""
- self._module.callgrind_start_instrumentation()
-
- def callgrind_stop_instrumentation(self) -> None:
- """Stop callgrind instrumentation."""
- self._module.callgrind_stop_instrumentation()
-
  def set_feature(self, feature: int, enabled: bool) -> None:
  """Set a feature flag in the instrument hooks library.