[GHC] #910: --make should have a -j flag for parallel building
GHC
ghc-devs at haskell.org
Sat Aug 31 00:18:16 UTC 2013
#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: 8184
Blocking: | Related Tickets:
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Comment (by parcs):
Replying to [comment:35 rrnewton]:
> By the way, I've had various hard-to-pin-down problems with changing
capabilities at runtime myself.
>
> Is it possible in this case to just disable the use of that feature for
the initial release? That is, you would have to use +RTS -N to get real
speedup. But, hey, it's kind of an advanced compilation feature anyway.
In this scenario we could get a lot of testing experience with parallel
builds without setNumCapabilities and then combine them when there is
higher confidence.
>
>
I don't mind going that route if the issue doesn't get sorted out soon. A
subsequent point release of GHC could reinstate the feature (automatically
setting the number of capabilities for the user), then. But I think I
could fix it on time.
----
Replying to [comment:34 simonmar]:
> The changes to handle loops look OK to me, but I would test it on a GHC
build to be sure. You want to build the whole of ghc/compiler with --make
-O2; the build system doesn't do this so you have to make a command line
by hand.
At first I couldn't even get GHC to compile itself via `--make -O2`
without `-j` (see #8184). Since that's been fixed I was able to build GHC
via `--make -O2 -j` after a minor tweak in the code, so the loop handling
should be solid now.
On to the `setNumCapabilities` issue...
--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/910#comment:38>
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