There is a thread on SWT mailing list regarding the increase in wait time on gerrit builds. In this regard I had reviewed the usage of executors on platform hipp and found that some of the jobs are configured to use CentOS executor only. This used to be a requirement when the master executor was on SLES 11. Now it has been upgraded to SLES12 which can be used for eclipse development. So I reconfigured gerrit jobs to use either of the executors based on availability.
Please keep a watch on unexpected errors/failures/problems and update Bug 509965 - Configure Gerrit jobs to use either SLES12 executor or CentOS executor in case of problems