Unneded string interpolation of characteristics is very resource hungry

[bobatsar]

The logger output in reactive_ble_mobile_platform.dart, is evaluated for each received message. Especially the interpolation of the characteristic is quite resource hungry. We are receiving a lot of characteristics data and this string interpolation takes up about 10-15% of CPU usage for our data handling.

flutter_reactive_ble/packages/reactive_ble_mobile/lib/src/reactive_ble_mobile_platform.dart

Lines 59 to 61 in 9aa9957

	_logger?.log(
	'Received $CharacteristicValue(characteristic: ${update.characteristic}, result: ${update.runtimeType})',
	);

Unfortunately the logger is always initialized via the following code and I don't see any way to disable it.

flutter_reactive_ble/packages/flutter_reactive_ble/lib/src/reactive_ble.dart

Lines 100 to 105 in 9aa9957

	Future<void> initialize() async {
	if (_initialization == null) {
	_debugLogger = DebugLogger(
	'REACTIVE_BLE',
	print,
	);

Can this be refactored, that the logger does not have to be initialized and can be set to null if not used? AFAIK then the interpolation would not be executed, resulting in less CPU usage.

[Taym95]

if you set logLevel to LogLevel.none you will disable logs

[bobatsar]

Hi @Taym95,

the issue is, that even when setting the logLevel to LogLevel.none the string interpolation still happens.
There is nothing is logged in the end but the calculations are already done. When the logger is set to null this does not happen.

Can you please reopen this ticket and also think about merging my PR #861?

[BenelliFurtado]

I noticed the same issue a few lines below. Our app is permanently scanning for Bluetooth devices and this is actually a big part of the used CPU!

flutter_reactive_ble/packages/reactive_ble_mobile/lib/src/reactive_ble_mobile_platform.dart

Lines 70 to 72 in 9aa9957

	_logger?.log(
	'Received $ScanResult(result: ${scanResult.result})',
	);

[BenelliFurtado]

Here is a screenshot from Flutter devtools. Notice the toString method in blue:

[bobatsar]

Hi @BenelliFurtado, yes that's the same issue. I am currently working on it and it seems my PR will be merged soon.