[SR-1143] [llbuild] Support for scheduling multithreaded tasks

[ddunbar]

Previous ID	SR-1143
Radar	rdar://problem/22640366
Original Reporter	@ddunbar
Type	Improvement

Additional Detail from JIRA

Votes	0
Component/s	llbuild
Labels	Improvement
Assignee	None
Priority	Medium

md5: 5f08aed889d0565e40a9ff9f13edb16c

relates to:

• SR-1141 [llbuild] Add support for understanding Swift parseable output

Issue Description:

We should support scheduling tasks which are multithreaded (for example, the Swift compiler) and which should recognized as consuming additional resources. Ideally this would be done in a way that we could automatically throttle appropriately once we have a mechanism for the Swift driver to tell us exactly how many threads it is using.

[ddunbar]

Related to:
https://bugs.swift.org/browse/SR-1141

[belkadan]

Is this really a starter bug?

[ddunbar]

No, unfortunately none of the llbuild bugs we have are "starter bugs", yet, but I thought it was better to have some "StarterBugs" in the llbuild component rather than none. I have a TODO to try and get real starter bugs and unlabel these but I can unlabel now if you think it is better.