#910: --make should have a -j flag for parallel building -------------------------------------+------------------------------------ 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: -------------------------------------+------------------------------------ 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> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler