1. 07 Aug, 2012 1 commit
  2. 06 Aug, 2012 1 commit
  3. 24 Jul, 2012 1 commit
  4. 12 Jun, 2012 1 commit
  5. 07 Jun, 2012 1 commit
    • Simon Marlow's avatar
      Fix for earger blackholing of thunks with no free variables (#6146) · 21a53a1c
      Simon Marlow authored
      A thunk with no free variables was not getting blackholed when
      -feager-blackholing was on, but we were nevertheless pushing the
      stg_bh_upd_frame version of the update frame that expects to see a
      black hole.
      
      I fixed this twice for good measure:
      
       - we now call blackHoleOnEntry when pushing the update frame to check
         whether the closure was actually blackholed, and so that we use the
         same predicate in both places
      
       - we now black hole thunks even if they have no free variables.
         These only occur when optimisation is off, but presumably if you say
         -feager-blackholing then that's what you want to happen.
      21a53a1c
  6. 23 Feb, 2012 1 commit
  7. 10 Jan, 2012 1 commit
    • dterei's avatar
      Track STG live register information for use in LLVM · 4384e146
      dterei authored
      We now carry around with CmmJump statements a list of
      the STG registers that are live at that jump site.
      This is used by the LLVM backend so it can avoid
      unnesecarily passing around dead registers, improving
      perfromance. This gives us the framework to finally
      fix trac #4308.
      4384e146
  8. 06 Jan, 2012 1 commit
  9. 05 Jan, 2012 1 commit
    • Simon Marlow's avatar
      Fixup to 4464c92b · 974f4510
      Simon Marlow authored
      Instead of enterLocalIdLabel we should get the label from the
      ClosureInfo, because that knows better whether the label should be
      local or not.
      
      Needed by #5357
      974f4510
  10. 04 Jan, 2012 1 commit
  11. 29 Nov, 2011 2 commits
    • Simon Marlow's avatar
      Make profiling work with multiple capabilities (+RTS -N) · 50de6034
      Simon Marlow authored
      This means that both time and heap profiling work for parallel
      programs.  Main internal changes:
      
        - CCCS is no longer a global variable; it is now another
          pseudo-register in the StgRegTable struct.  Thus every
          Capability has its own CCCS.
      
        - There is a new built-in CCS called "IDLE", which records ticks for
          Capabilities in the idle state.  If you profile a single-threaded
          program with +RTS -N2, you'll see about 50% of time in "IDLE".
      
        - There is appropriate locking in rts/Profiling.c to protect the
          shared cost-centre-stack data structures.
      
      This patch does enough to get it working, I have cut one big corner:
      the cost-centre-stack data structure is still shared amongst all
      Capabilities, which means that multiple Capabilities will race when
      updating the "allocations" and "entries" fields of a CCS.  Not only
      does this give unpredictable results, but it runs very slowly due to
      cache line bouncing.
      
      It is strongly recommended that you use -fno-prof-count-entries to
      disable the "entries" count when profiling parallel programs. (I shall
      add a note to this effect to the docs).
      50de6034
    • Simon Marlow's avatar
      Get rid of the "safety" field of CmmCall (OldCmm) · cbe24168
      Simon Marlow authored
      This field was doing nothing.  I think it originally appeared in a
      very old incarnation of the new code generator.
      cbe24168
  12. 04 Nov, 2011 1 commit
  13. 02 Nov, 2011 1 commit
    • Simon Marlow's avatar
      Overhaul of infrastructure for profiling, coverage (HPC) and breakpoints · 7bb0447d
      Simon Marlow authored
      User visible changes
      ====================
      
      Profilng
      --------
      
      Flags renamed (the old ones are still accepted for now):
      
        OLD            NEW
        ---------      ------------
        -auto-all      -fprof-auto
        -auto          -fprof-exported
        -caf-all       -fprof-cafs
      
      New flags:
      
        -fprof-auto              Annotates all bindings (not just top-level
                                 ones) with SCCs
      
        -fprof-top               Annotates just top-level bindings with SCCs
      
        -fprof-exported          Annotates just exported bindings with SCCs
      
        -fprof-no-count-entries  Do not maintain entry counts when profiling
                                 (can make profiled code go faster; useful with
                                 heap profiling where entry counts are not used)
      
      Cost-centre stacks have a new semantics, which should in most cases
      result in more useful and intuitive profiles.  If you find this not to
      be the case, please let me know.  This is the area where I have been
      experimenting most, and the current solution is probably not the
      final version, however it does address all the outstanding bugs and
      seems to be better than GHC 7.2.
      
      Stack traces
      ------------
      
      +RTS -xc now gives more information.  If the exception originates from
      a CAF (as is common, because GHC tends to lift exceptions out to the
      top-level), then the RTS walks up the stack and reports the stack in
      the enclosing update frame(s).
      
      Result: +RTS -xc is much more useful now - but you still have to
      compile for profiling to get it.  I've played around a little with
      adding 'head []' to GHC itself, and +RTS -xc does pinpoint the problem
      quite accurately.
      
      I plan to add more facilities for stack tracing (e.g. in GHCi) in the
      future.
      
      Coverage (HPC)
      --------------
      
       * derived instances are now coloured yellow if they weren't used
       * likewise record field names
       * entry counts are more accurate (hpc --fun-entry-count)
       * tab width is now correct (markup was previously off in source with
         tabs)
      
      Internal changes
      ================
      
      In Core, the Note constructor has been replaced by
      
              Tick (Tickish b) (Expr b)
      
      which is used to represent all the kinds of source annotation we
      support: profiling SCCs, HPC ticks, and GHCi breakpoints.
      
      Depending on the properties of the Tickish, different transformations
      apply to Tick.  See CoreUtils.mkTick for details.
      
      Tickets
      =======
      
      This commit closes the following tickets, test cases to follow:
      
        - Close #2552: not a bug, but the behaviour is now more intuitive
          (test is T2552)
      
        - Close #680 (test is T680)
      
        - Close #1531 (test is result001)
      
        - Close #949 (test is T949)
      
        - Close #2466: test case has bitrotted (doesn't compile against current
          version of vector-space package)
      7bb0447d
  14. 17 Oct, 2011 2 commits
  15. 06 Sep, 2011 1 commit
  16. 25 Aug, 2011 1 commit
  17. 11 Apr, 2011 1 commit
  18. 24 Jan, 2011 1 commit
    • Simon Marlow's avatar
      Merge in new code generator branch. · 889c084e
      Simon Marlow authored
      This changes the new code generator to make use of the Hoopl package
      for dataflow analysis.  Hoopl is a new boot package, and is maintained
      in a separate upstream git repository (as usual, GHC has its own
      lagging darcs mirror in http://darcs.haskell.org/packages/hoopl).
      
      During this merge I squashed recent history into one patch.  I tried
      to rebase, but the history had some internal conflicts of its own
      which made rebase extremely confusing, so I gave up. The history I
      squashed was:
      
        - Update new codegen to work with latest Hoopl
        - Add some notes on new code gen to cmm-notes
        - Enable Hoopl lag package.
        - Add SPJ note to cmm-notes
        - Improve GC calls on new code generator.
      
      Work in this branch was done by:
         - Milan Straka <fox@ucw.cz>
         - John Dias <dias@cs.tufts.edu>
         - David Terei <davidterei@gmail.com>
      
      Edward Z. Yang <ezyang@mit.edu> merged in further changes from GHC HEAD
      and fixed a few bugs.
      889c084e
  19. 29 Mar, 2010 1 commit
    • Simon Marlow's avatar
      New implementation of BLACKHOLEs · 5d52d9b6
      Simon Marlow authored
      This replaces the global blackhole_queue with a clever scheme that
      enables us to queue up blocked threads on the closure that they are
      blocked on, while still avoiding atomic instructions in the common
      case.
      
      Advantages:
      
       - gets rid of a locked global data structure and some tricky GC code
         (replacing it with some per-thread data structures and different
         tricky GC code :)
      
       - wakeups are more prompt: parallel/concurrent performance should
         benefit.  I haven't seen anything dramatic in the parallel
         benchmarks so far, but a couple of threading benchmarks do improve
         a bit.
      
       - waking up a thread blocked on a blackhole is now O(1) (e.g. if
         it is the target of throwTo).
      
       - less sharing and better separation of Capabilities: communication
         is done with messages, the data structures are strictly owned by a
         Capability and cannot be modified except by sending messages.
      
       - this change will utlimately enable us to do more intelligent
         scheduling when threads block on each other.  This is what started
         off the whole thing, but it isn't done yet (#3838).
      
      I'll be documenting all this on the wiki in due course.
      5d52d9b6
  20. 31 Dec, 2009 1 commit
  21. 06 Nov, 2009 1 commit
    • Ben.Lippmeier@anu.edu.au's avatar
      * Refactor CLabel.RtsLabel to CLabel.CmmLabel · a02e7f40
      Ben.Lippmeier@anu.edu.au authored
      The type of the CmmLabel ctor is now
        CmmLabel :: PackageId -> FastString -> CmmLabelInfo -> CLabel
        
       - When you construct a CmmLabel you have to explicitly say what
         package it is in. Many of these will just use rtsPackageId, but
         I've left it this way to remind people not to pretend labels are
         in the RTS package when they're not. 
         
       - When parsing a Cmm file, labels that are not defined in the 
         current file are assumed to be in the RTS package. 
         
         Labels imported like
            import label
         are assumed to be in a generic "foreign" package, which is different
         from the current one.
         
         Labels imported like
            import "package-name" label
         are marked as coming from the named package.
         
         This last one is needed for the integer-gmp library as we want to
         refer to labels that are not in the same compilation unit, but
         are in the same non-rts package.
         
         This should help remove the nasty #ifdef __PIC__ stuff from
         integer-gmp/cbits/gmp-wrappers.cmm
         
      a02e7f40
  22. 18 Oct, 2009 1 commit
  23. 30 Sep, 2009 1 commit
  24. 31 Mar, 2009 1 commit
  25. 18 Dec, 2008 1 commit
  26. 17 Dec, 2008 1 commit
  27. 14 Aug, 2008 1 commit
    • dias@eecs.harvard.edu's avatar
      Merging in the new codegen branch · 176fa33f
      dias@eecs.harvard.edu authored
      This merge does not turn on the new codegen (which only compiles
      a select few programs at this point),
      but it does introduce some changes to the old code generator.
      
      The high bits:
      1. The Rep Swamp patch is finally here.
         The highlight is that the representation of types at the
         machine level has changed.
         Consequently, this patch contains updates across several back ends.
      2. The new Stg -> Cmm path is here, although it appears to have a
         fair number of bugs lurking.
      3. Many improvements along the CmmCPSZ path, including:
         o stack layout
         o some code for infotables, half of which is right and half wrong
         o proc-point splitting
      176fa33f
  28. 18 Nov, 2008 1 commit
    • Simon Marlow's avatar
      Add optional eager black-holing, with new flag -feager-blackholing · d600bf7a
      Simon Marlow authored
      Eager blackholing can improve parallel performance by reducing the
      chances that two threads perform the same computation.  However, it
      has a cost: one extra memory write per thunk entry.  
      
      To get the best results, any code which may be executed in parallel
      should be compiled with eager blackholing turned on.  But since
      there's a cost for sequential code, we make it optional and turn it on
      for the parallel package only.  It might be a good idea to compile
      applications (or modules) with parallel code in with
      -feager-blackholing.
      
      ToDo: document -feager-blackholing.
      d600bf7a
  29. 03 May, 2008 1 commit
  30. 12 Apr, 2008 1 commit
  31. 04 Jan, 2008 1 commit
  32. 04 Sep, 2007 1 commit
  33. 03 Sep, 2007 1 commit
  34. 01 Sep, 2007 1 commit
  35. 27 Jul, 2007 1 commit
    • Simon Marlow's avatar
      Pointer Tagging · 6015a94f
      Simon Marlow authored
        
      This patch implements pointer tagging as per our ICFP'07 paper "Faster
      laziness using dynamic pointer tagging".  It improves performance by
      10-15% for most workloads, including GHC itself.
      
      The original patches were by Alexey Rodriguez Yakushev
      <mrchebas@gmail.com>, with additions and improvements by me.  I've
      re-recorded the development as a single patch.
      
      The basic idea is this: we use the low 2 bits of a pointer to a heap
      object (3 bits on a 64-bit architecture) to encode some information
      about the object pointed to.  For a constructor, we encode the "tag"
      of the constructor (e.g. True vs. False), for a function closure its
      arity.  This enables some decisions to be made without dereferencing
      the pointer, which speeds up some common operations.  In particular it
      enables us to avoid costly indirect jumps in many cases.
      
      More information in the commentary:
      
      http://hackage.haskell.org/trac/ghc/wiki/Commentary/Rts/HaskellExecution/PointerTagging
      6015a94f
  36. 02 Jul, 2007 1 commit
  37. 27 Jun, 2007 2 commits