[GHC] #910: --make should have a -j flag for parallel building

[GHC]

#910: --make should have a -j flag for parallel building
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        Reporter:  igloo             |            Owner:
            Type:  feature request   |           Status:  patch
        Priority:  normal            |        Milestone:  _|_
       Component:  Compiler          |          Version:  6.4.2
      Resolution:                    |         Keywords:
Operating System:  Unknown/Multiple  |     Architecture:  Unknown/Multiple
 Type of failure:  None/Unknown      |       Difficulty:  Unknown
       Test Case:  N/A               |       Blocked By:
        Blocking:                    |  Related Tickets:
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Comment (by rrnewton):

 Thanks for doing the work on this!  Very exciting.  I for one will start
 testing it.

 I started reading the code a bit and have one question.  But first, thanks
 for producing well-documented code---very readable!  My question has to do
 with the banal issue of printing stuff out in parallel, which can often be
 quite ugly.

 I like that the normal compilation output is directed to a per-module
 TQueue.  But what about printed exceptions when they occur?

 I see that you've got three "[g]bracket" calls in the parallel upsweep,
 and that you take care to kill worker threads (asychronously) when an
 exception occurs.  However, I don't see a general catch-all for exceptions
 at the top of each worker thread (such as in Control.Async).  In my
 experience exceptions on child threads can be a real pain.  For example,
 if a worker thread dies... it looks like other threads may be blocked
 indefinitely waiting on the result MVar?

 Apologies if I've missed something...

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/910#comment:24>
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