Comment 1 for bug 478691

I'm not sure how to best deal with this. The fix from bug 393546 has not worked as well as hoped.

The best idea so far is to reduce the number of concurrent long-running builds that a single PPA can have on a dynamic basis; that is allow them to increase in concurrency based on a few factors like:

 * empty queues on some builders
 * length of build (e.g. 1 fewer concurrent build for every 30 minutes of build time queued)

I welcome more suggestions if you can think of anything.