I have some jobs which have lots of artifacts (over 5000 files in over 400 folders). When i retrieve build details of job run via REST api (e.g. https://jenkins/job/JenkinsJob/123/api/xml) then a huge response XML document has to be created. With the last LTS version (1.625.3) this wasn't an issue but after upgrading (1.642.1) I have noticed an extremely high CPU load (over 95%).

By the use of Visual VM I was able to identify three methods which are using a lot of CPU time (see screenshot):

• jenkins.util.VirtualFile$FileVF,isIllegalSymlink()
• com4j.Win32Lock.suspend1[native]()
• org.eclipse.jetty.io.nio.SelectorManager$SelectSet.doSelect()

This problem occurred after upgrading from 1.625.3 to 1.642.1. The requests are not send by an internal application. I assume that the Hudson Tray Tracker is responsible for the problem (I will try to create a patch for this application but anyway I think that there is an performance issue)