Support Core plugins from 2.42 to 2.44 performs histo:live requests periodically thus a FullGC is also performed.
Jenkins instances requiring more than 10G of heap could face slowness issues because of the FullGC.
Upgrade Support Core plugin to 2.45.1 or higher.
Since 2.42 to 2.44, a new component requests the memory histogram for live instances. In order to generate the histogram, the jvm performs a FullGC. That behavior cannot be disabled when the bundle is generated in background.
Support Core plugin 2.45.1 disables the histogram generation by default, but can be enabled:
com.cloudbees.jenkins.support.impl.HeapUsageHistogram.DISABLED=falsefrom Manage Jenkins / Script Console