perf(smartfuel): keep the configuration and compare the restart values instead of rebuilding both every wake

release-notes/smartfuel-config-hoist.build.md

@@ -0,0 +1,2 @@
+- **SmartFuel no longer rebuilds its configuration and reset signature on every wake (`tasks/events/telemetry_bg/smart.lua`)**:
+  - `Smart.wakeup` computes once a second in every Lua state that runs the event runtime (the dashboard and service widgets, the tool). Each of those wakes built a new configuration table through three fresh closures and a parsed API version, although the configuration only changes when a setting does, and joined seven `tostring` results into a string to decide whether to restart the estimate, although those values only change with the settings, the battery configuration, the active battery profile or the pack's cell count. The helpers are now file-level functions, the configuration is rebuilt only when one of its input values differs from the last wake (compared by value, so a page writing into the session's tables in place is still seen), and the restart test compares the seven values field by field. Measured on desktop Lua 5.3, a computing wake with unchanged inputs allocates nothing instead of 945 bytes, and costs 510 instructions instead of 697 (firmware source) or 749 instead of 927 (local voltage source). The configuration and every restart decision are unchanged, with one exception: the restart values are now compared as numbers, so a value that changes only between an integer and a float of the same size (a cell count reported as `6.0` where it was `6`, a capacity of `2000.0` where it was `2000`) no longer restarts the estimate. The string comparison restarted it, because Lua 5.3 prints the two differently (#768).

src/rfsuite/tasks/events/telemetry_bg/smart.lua

@@ -17,8 +17,8 @@ local lastWake = 0
 local wakeInterval = 1.0
 
 local state = {
-  batterySignature = nil,
-  sourceMode = nil,
+  batterySignature = {},
+  signatureValid = false,
   stabilizeUntil = 0,
   voltageSamples = {},
   voltageStable = false,
@@ -225,60 +225,105 @@ local function scaleField(raw, fallback, minValue, maxValue, scale)
   return value
 end
 
-local function getSmartConfig(session)
-  local cfg = session and session.smartfuel_config or nil
-  local batteryPrefs = session and session.modelPreferences and session.modelPreferences.battery or nil
-
-  local function readLegacyLocalSource()
-    local source = batteryPrefs and tonumber(batteryPrefs.smartfuel_source) or nil
-    if source == nil then
-      source = batteryPrefs and tonumber(batteryPrefs.calc_local) or nil
-    end
-    return source
-  end
+local FIRMWARE_SOURCE_MIN_API = { 12, 0, 9 }
 
-  local function getFirmwareSource()
-    local apiVersion = ApiVersion and ApiVersion.parse and ApiVersion.parse(session and session.apiVersion)
-    if not (ApiVersion and ApiVersion.isAtLeast and ApiVersion.isAtLeast(apiVersion, { 12, 0, 9 })) then
-      return nil
-    end
-    local mode = cfg and tonumber(cfg.smartfuel_mode) or nil
-    if mode == nil then
-      local batteryConfig = session and session.battery_config
-      mode = batteryConfig and tonumber(batteryConfig.smartfuelRemoteSource) or nil
-    end
-    return mode
+local function readLegacyLocalSource(batteryPrefs)
+  local source = batteryPrefs and tonumber(batteryPrefs.smartfuel_source) or nil
+  if source == nil then
+    source = batteryPrefs and tonumber(batteryPrefs.calc_local) or nil
   end
+  return source
+end
 
-  local function pick(key)
-    if cfg and cfg[key] ~= nil then return cfg[key] end
-    if batteryPrefs and batteryPrefs[key] ~= nil then return batteryPrefs[key] end
+local function getFirmwareSource(session, cfg)
+  local apiVersion = ApiVersion and ApiVersion.parse and ApiVersion.parse(session and session.apiVersion)
+  if not (ApiVersion and ApiVersion.isAtLeast and ApiVersion.isAtLeast(apiVersion, FIRMWARE_SOURCE_MIN_API)) then
     return nil
   end
+  local mode = cfg and tonumber(cfg.smartfuel_mode) or nil
+  if mode == nil then
+    local batteryConfig = session and session.battery_config
+    mode = batteryConfig and tonumber(batteryConfig.smartfuelRemoteSource) or nil
+  end
+  return mode
+end
+
+local function pick(cfg, batteryPrefs, key)
+  if cfg and cfg[key] ~= nil then return cfg[key] end
+  if batteryPrefs and batteryPrefs[key] ~= nil then return batteryPrefs[key] end
+  return nil
+end
+
+-- The configuration is a function of the thirteen values read at the top of getSmartConfig and of
+-- nothing else, and they change only when a setting or the flight controller's configuration does
+-- -- while the configuration is read on every wake that computes. So the values it was last built
+-- from are kept here, and the table is rebuilt only when one of them differs. They are compared by
+-- value, not by the identity of the tables they come from: the SmartFuel and battery pages write
+-- into the session's tables in place.
+local configInputs = {
+  apiVersion = false, mode = false, remoteSource = false, localSource = false, calcLocal = false,
+  publish = false, voltageDropRate = false, chargeDropRate = false, sagGain = false,
+  voltageFallLimit = false, fuelDropRate = false, stabilizeDelay = false, stableWindow = false,
+}
+local smartConfig = nil
 
-  local source = readLegacyLocalSource()
+local function getSmartConfig(session)
+  local cfg = session and session.smartfuel_config or nil
+  local batteryPrefs = session and session.modelPreferences and session.modelPreferences.battery or nil
+  local batteryConfig = session and session.battery_config
+
+  local apiVersion = session and session.apiVersion
+  local mode = cfg and cfg.smartfuel_mode
+  local remoteSource = batteryConfig and batteryConfig.smartfuelRemoteSource
+  local localSource = batteryPrefs and batteryPrefs.smartfuel_source
+  local calcLocal = batteryPrefs and batteryPrefs.calc_local
+  local publish = batteryPrefs and batteryPrefs.smartfuel_publish
+  local voltageDropRate = pick(cfg, batteryPrefs, "voltage_drop_rate")
+  local chargeDropRate = pick(cfg, batteryPrefs, "charge_drop_rate")
+  local sagGain = pick(cfg, batteryPrefs, "sag_gain")
+  local voltageFallLimit = pick(cfg, batteryPrefs, "voltage_fall_limit")
+  local fuelDropRate = pick(cfg, batteryPrefs, "fuel_drop_rate")
+  local stabilizeDelay = pick(cfg, batteryPrefs, "stabilize_delay")
+  local stableWindow = pick(cfg, batteryPrefs, "stable_window")
+
+  local last = configInputs
+  if smartConfig
+    and last.apiVersion == apiVersion and last.mode == mode and last.remoteSource == remoteSource
+    and last.localSource == localSource and last.calcLocal == calcLocal and last.publish == publish
+    and last.voltageDropRate == voltageDropRate and last.chargeDropRate == chargeDropRate
+    and last.sagGain == sagGain and last.voltageFallLimit == voltageFallLimit
+    and last.fuelDropRate == fuelDropRate and last.stabilizeDelay == stabilizeDelay
+    and last.stableWindow == stableWindow then
+    return smartConfig
+  end
+  last.apiVersion, last.mode, last.remoteSource = apiVersion, mode, remoteSource
+  last.localSource, last.calcLocal, last.publish = localSource, calcLocal, publish
+  last.voltageDropRate, last.chargeDropRate, last.sagGain = voltageDropRate, chargeDropRate, sagGain
+  last.voltageFallLimit, last.fuelDropRate = voltageFallLimit, fuelDropRate
+  last.stabilizeDelay, last.stableWindow = stabilizeDelay, stableWindow
+
+  local source = readLegacyLocalSource(batteryPrefs)
   if source == nil then source = 0 end
 
-  local voltageDropRate = tonumber(pick("voltage_drop_rate"))
-  local chargeDropRate = tonumber(pick("charge_drop_rate"))
-  local sagGain = tonumber(pick("sag_gain")) or 40
+  voltageDropRate = tonumber(voltageDropRate)
+  chargeDropRate = tonumber(chargeDropRate)
 
   local voltageFallPerSecond = nil
   if voltageDropRate ~= nil then
     voltageFallPerSecond = voltageDropRate / 1000
   else
-    voltageFallPerSecond = scaleField(pick("voltage_fall_limit"), 0.05, 0, 1, 100)
+    voltageFallPerSecond = scaleField(voltageFallLimit, 0.05, 0, 1, 100)
   end
 
   local fuelDropPerSecond = nil
   if chargeDropRate ~= nil then
     fuelDropPerSecond = chargeDropRate / 100
   else
-    fuelDropPerSecond = scaleField(pick("fuel_drop_rate"), 1.0, 0, 50, 10)
+    fuelDropPerSecond = scaleField(fuelDropRate, 1.0, 0, 50, 10)
   end
 
-  return {
-    firmwareSource = getFirmwareSource(),
+  smartConfig = {
+    firmwareSource = getFirmwareSource(session, cfg),
     source = source,
     -- Whether the two sensors are published at all. Read from the model's own preferences and
     -- deliberately NOT through `pick`: `pick` lets the flight controller's SmartFuel
@@ -291,12 +336,13 @@ local function getSmartConfig(session)
     -- on SmFt survives the update. Nothing inside the suite depends on it either way -- those
     -- consumers are served by the hand-over below.
     publishSensors = (batteryPrefs and batteryPrefs.smartfuel_publish) ~= false,
-    stabilizeDelaySeconds = scaleField(pick("stabilize_delay"), 1.5, 0, 10, 1000),
-    stableWindowVolts = scaleField(pick("stable_window"), 0.15, 0, 1, 100),
+    stabilizeDelaySeconds = scaleField(stabilizeDelay, 1.5, 0, 10, 1000),
+    stableWindowVolts = scaleField(stableWindow, 0.15, 0, 1, 100),
     voltageFallPerSecond = voltageFallPerSecond,
     fuelDropPerSecond = fuelDropPerSecond,
-    sagGain = sagGain
+    sagGain = tonumber(sagGain) or 40
   }
+  return smartConfig
 end
 
 -- Firmware with per-profile battery cells (tasks/msp/api/battery_config.lua, `hasProfileCells`)
@@ -603,19 +649,28 @@ function Smart.wakeup()
     return
   end
 
-  local signature = table.concat({
-    tostring(firmwareSource or "nil"),
-    tostring(sourceMode),
-    tostring(cellCount),
-    tostring(packCapacity),
-    tostring(reserve),
-    tostring((tonumber(batteryConfig.vbatmincellvoltage) or 0)),
-    tostring((tonumber(batteryConfig.vbatfullcellvoltage) or 0))
-  }, ":")
-
-  if state.batterySignature ~= signature or state.sourceMode ~= sourceMode then
-    state.batterySignature = signature
-    state.sourceMode = sourceMode
+  -- The estimate restarts when any of these differs from the values it was started with. Compared
+  -- field by field: joining them into a string to compare cost a table and seven strings on every
+  -- wake that got this far.
+  local minCellVoltage = tonumber(batteryConfig.vbatmincellvoltage) or 0
+  local fullCellVoltage = tonumber(batteryConfig.vbatfullcellvoltage) or 0
+  local signature = state.batterySignature
+  if not state.signatureValid
+    or signature.firmwareSource ~= firmwareSource
+    or signature.sourceMode ~= sourceMode
+    or signature.cellCount ~= cellCount
+    or signature.packCapacity ~= packCapacity
+    or signature.reserve ~= reserve
+    or signature.minCellVoltage ~= minCellVoltage
+    or signature.fullCellVoltage ~= fullCellVoltage then
+    signature.firmwareSource = firmwareSource
+    signature.sourceMode = sourceMode
+    signature.cellCount = cellCount
+    signature.packCapacity = packCapacity
+    signature.reserve = reserve
+    signature.minCellVoltage = minCellVoltage
+    signature.fullCellVoltage = fullCellVoltage
+    state.signatureValid = true
     state.stabilizeUntil = now + cfg.stabilizeDelaySeconds
     resetComputedState()
     logSmart("smart reset source=" .. tostring(sourceMode) .. " cap=" .. tostring(packCapacity), "info")
@@ -687,8 +742,8 @@ end
 
 function Smart.reset()
   clearHandOver()
-  state.batterySignature = nil
-  state.sourceMode = nil
+  state.signatureValid = false
+  smartConfig = nil
   state.stabilizeUntil = 0
   state.lastFuelValue = nil
   state.lastFuelPush = 0