[LOG4J2-1318] LoggerContext#getLogger causes heavy GC overhead

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.5
• Fix Version/s: 2.6
• Component/s: Core
• Labels: performance
• Flags: Important
• Epic Link: GC-free
• Assignee: Remko Popma
• Reporter: Rodrigo Merino
• Created: 16/Mar/16 20:49
• Updated: 28/Mar/16 20:55
• Resolved: 28/Mar/16 00:09

Description

With the changes from LOG4J2-1180, when running performance testing scenarios, we are experiencing some throughput degradations due to an increase in the GC stall time.

With the changes from LOG4J2-1180, the GC stall went from ~6% to ~11%, having an impact on the application of a reduction of ~32% of the operations throughput. The memory allocation rate both before and after the change is 4GB/s and 12GB/s respectively.

In both cases, the relevant jvm configuration params were:

-XX:+PrintGCApplicationStoppedTime -XX:+PrintGCDetails -XX:+PrintGCDateStamps -XX:+PrintTenuringDistribution -XX:ErrorFile=%MHOME%/logs/err.log -Xloggc:%HOME%/logs/gc.log -XX:+HeapDumpOnOutOfMemoryError -XX:+AlwaysPreTouch -Xms2048m -XX:PermSize=256m -XX:MaxPermSize=256m -XX:+UseParNewGC -XX:NewSize=1024m -XX:+UseNUMA