[GHC] #10228: Increased memory usage with GHC 7.10.1

[GHC]

#10228: Increased memory usage with GHC 7.10.1
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              Reporter:  jstolarek   |             Owner:
                  Type:  bug         |            Status:  new
              Priority:  normal      |         Milestone:
             Component:  Compiler    |           Version:  7.10.1
              Keywords:              |  Operating System:  Unknown/Multiple
          Architecture:              |   Type of failure:  Compile-time
  Unknown/Multiple                   |  performance bug
             Test Case:              |        Blocked By:
              Blocking:              |   Related Tickets:
Differential Revisions:              |
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 (Repost from ghc-devs)

 I just uprgaded both of my machines to use GHC 7.10.1. I keep sandboxed
 installations of GHC and this means I had to rebuild Agda and Idris
 because the binaries built with GHC 7.8.4 were stored inside deactivated
 7.8.4 sandbox. Sadly, I had problems building both Agda and Idris due to
 GHC taking up all of available memory.

 With Idris the problematic module was Idris.ElabTerm (~2900LOC). The
 interesting part of the story is that when I do a clean build of Idris GHC
 consumes all of memory when compiling that module and I have to kill the
 build. But when I restart the build after killing GHC the module is
 compiled using a reasonable amount of memory and within reasonable time.

 With Agda the problematic module is Agda.TypeChecking.Serialise
 (~2000LOC). The trick with killing the build and restarting it didn't work
 in this case. I had to compile Agda with GHC 7.8.4 (which works without
 problems though the mentioned module still requires a lot of memory) and
 alter my setup so that Agda binary is not stored inside GHC sandbox.

 I wonder if any of you came across similar issues with GHC 7.10.1? Do we
 have any performance data that allows to compare memory usage and
 performance of GHC 7.10.1 with previous stable releases?

 All of the above happened on 64bit Debian Wheezy with 2GB of RAM.

 On my second machine, this time with 4GB of RAM, compiling Agda ran out of
 memory (again Agda.TypeChecking.Serialise module) and I had to kill the
 build. But once I restarted the build the module was compiled succesfully
 in a matter of minutes and using around 50% of memory.

 This looks like some kind of memory leak in GHC.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10228>
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