Killing obsolete Jenkins builds

(Sorry if this has already been discussed/considered.)

Once a patch is pushed to Gerrit a Jenkins build automatically starts. And
once subsequent patches are pushed the cycle repeats.

Is there a reason to keep running the builds of (old) patches that will not
get cherry picked?

How much effort is necessary to stop builds for a given Gerrit push before
starting new ones? (I'm assuming the Gerrit ID will be used and a command
to kill all build configurations.)

To me it looks completely wasteful to spend hours building a few patches
that were pushed one after the other when only the last one is relevant.
Not only it is wasteful to valuable shared resources, but the user is
punished for making a change too soon and now has to wait an extended time
before the last patch is built.



As an aside, the recent drop in average build times (visible from the
Jenkins build times list/graph) is something I like to believe is my fault
:) The relevant commits were pushed on Sunday last and now there are far
more sub 1h builds and the peaks for longer builds are shorter. I like to
reduce that average even further by avoiding wasting the machine cycles on
irrelevant work.

Thanks.