Async Logger

Async Logger is a Minecraft mod that makes logging operations asynchronous.

In vanilla, loggers are not asynchronous. This means the actual logging operations, including I/O operations, happen on the logging thread. This mod changes logging to be asynchronous for better performance.

This can be especially useful when large amounts of messages are being logged and/or debug logging is enabled (default on Forge / NeoForge).

Benchmarks

Item	Vanilla	AsyncLogger
Simple Messages (10k)	6146.1ms	141.2ms
Messages with Placeholders (10k)	6413.2ms	96.6ms
Messages with Throwable (1.5k)	19572.4ms	9.0ms

You can do these tests yourself by enabling testPerformance in the config. When this option is enabled, the mod will log a large number of messages both before and after setting up async loggers. You can see the test results in the log.

Filtering

Starting from version 2.0.0, AsyncLogger supports log filtering. The filtering happens on the dedicated, async logger thread, ensuring there is no overhead for the caller.

To use, simply set filtering.enabled to true in the config, and edit one or more of the filters. Filtering by logger name, level, and message (match substring or regexps) is supported.

Technical Details

• Asynchronous loggers are used, in favor of Asynchronous appenders. The former is newer, faster and lighter on allocation rate.
  • Asynchronous loggers require LMAX Disruptor, a lock-free inter-thread communication library. The mod will load the library onto the system classloader when it is not present. This mod redistributes LMAX Disruptor under the Apache-2.0 License.
• The config file allows easy control of some log4j2 settings.
• System.out and System.err can be redirected to loggers.