Daniel Knittl-Frank created LOGBACK-1476: -------------------------------------------- Summary: Avoid synchronized blocks when copying MDC to a function-local map Key: LOGBACK-1476 URL: https://jira.qos.ch/browse/LOGBACK-1476 Project: logback Issue Type: Improvement Reporter: Daniel Knittl-Frank Assignee: Logback dev list When setting or duplicating the MDC context map, a synchronized map is used. This incurs the overhead of locking when putting key-value pairs into the map. This overhead can be avoided, because the map is method-local and only a single thread can access it a single time. Delay wrapping the map in a synchronizedMap until before it leaves the scope of the method. You can find the proposed changes in [https://github.com/qos-ch/logback/pull/462|https://github.com/qos-ch/logback/pull/462/files] I have not performed any benchmarks and would appreciate if somebody could write some. Maybe the JVM is already clever enough to detect this useless synchronization and elides the lock? -- This message was sent by Atlassian JIRA (v7.3.1#73012)