move lru_cache to ul_per_mm

api/src/opentrons/hardware_control/instrument_handler.py

@@ -1,5 +1,4 @@
 """Shared code for managing pipette configuration and storage."""
-import functools
 from dataclasses import dataclass
 import logging
 from typing import (
@@ -50,8 +49,6 @@
 
 AxisType = TypeVar("AxisType", Axis, OT3Axis)
 
-PLUNGER_CACHE_LIMIT = 32
-
 
 @dataclass(frozen=True)
 class LiquidActionSpec(Generic[AxisType]):
@@ -396,22 +393,19 @@ def ready_for_tip_action(self, target: Pipette, action: HardwareAction) -> None:
             raise RuntimeError("Pipette not ready to aspirate")
         self._ihp_log.debug(f"{action} on {target.name}")
 
-    @functools.lru_cache(PLUNGER_CACHE_LIMIT)
     def plunger_position(
         self, instr: Pipette, ul: float, action: "UlPerMmAction"
     ) -> float:
         mm = ul / instr.ul_per_mm(ul, action)
         position = mm + instr.config.bottom
         return round(position, 6)
 
-    @functools.lru_cache(PLUNGER_CACHE_LIMIT)
     def plunger_speed(
         self, instr: Pipette, ul_per_s: float, action: "UlPerMmAction"
     ) -> float:
         mm_per_s = ul_per_s / instr.ul_per_mm(instr.config.max_volume, action)
         return round(mm_per_s, 6)
 
-    @functools.lru_cache(PLUNGER_CACHE_LIMIT)
     def plunger_flowrate(
         self, instr: Pipette, mm_per_s: float, action: "UlPerMmAction"
     ) -> float:
@@ -902,7 +896,6 @@ def get_pipette(self, mount: MountType) -> Pipette:
 class OT3InstrumentHandler(InstrumentHandlerProvider[OT3Mount]):
     """Override for correct plunger_position."""
 
-    @functools.lru_cache(PLUNGER_CACHE_LIMIT)
     def plunger_position(
         self, instr: Pipette, ul: float, action: "UlPerMmAction"
     ) -> float:

api/src/opentrons/hardware_control/pipette.py

@@ -1,5 +1,7 @@
 from __future__ import annotations
 
+import functools
+
 """ Classes and functions for pipette state tracking
 """
 from dataclasses import asdict, replace
@@ -287,6 +289,9 @@ def remove_tip(self) -> None:
     def has_tip(self) -> bool:
         return self._has_tip
 
+    # Cache max is chosen somewhat arbitrarily. With a float is input we don't
+    # want this to unbounded.
+    @functools.lru_cache(maxsize=100)
     def ul_per_mm(self, ul: float, action: UlPerMmAction) -> float:
         sequence = self._config.ul_per_mm[action]
         return pipette_config.piecewise_volume_conversion(ul, sequence)