On the buildTimeTrend page there is a list of builds: how long they took and
where they were executed. In our case the slave column shows always "(master)"
although these jobs were executed remotely on another host.

Build ↑ Duration Slave
#23 9 minutes (master)
#22 8 minutes (master)
#21 7 minutes (master)
#20 1 minute (master)
#19 15 minutes (master)
#18 7 minutes (master)
#17 6 minutes (master)
#16 7 minutes (master)
#15 8 minutes (master)