1. 15 Jun, 2013 1 commit
    • aljee@hyper.cx's avatar
      Allow multiple C finalizers to be attached to a Weak# · d61c623e
      aljee@hyper.cx authored
      The commit replaces mkWeakForeignEnv# with addCFinalizerToWeak#.
      This new primop mutates an existing Weak# object and adds a new
      C finalizer to it.
      
      This change removes an invariant in MarkWeak.c, namely that the relative
      order of Weak# objects in the list needs to be preserved across GC. This
      makes it easier to split the list into per-generation structures.
      
      The patch also removes a race condition between two threads calling
      finalizeWeak# on the same WEAK object at that same time.
      d61c623e
  2. 05 May, 2010 1 commit
  3. 17 Dec, 2009 1 commit
    • Simon Marlow's avatar
      Fix #650: use a card table to mark dirty sections of mutable arrays · 0417404f
      Simon Marlow authored
      The card table is an array of bytes, placed directly following the
      actual array data.  This means that array reading is unaffected, but
      array writing needs to read the array size from the header in order to
      find the card table.
      
      We use a bytemap rather than a bitmap, because updating the card table
      must be multi-thread safe.  Each byte refers to 128 entries of the
      array, but this is tunable by changing the constant
      MUT_ARR_PTRS_CARD_BITS in includes/Constants.h.
      0417404f
  4. 01 Dec, 2009 1 commit
    • Simon Marlow's avatar
      Make allocatePinned use local storage, and other refactorings · 5270423a
      Simon Marlow authored
      This is a batch of refactoring to remove some of the GC's global
      state, as we move towards CPU-local GC.  
      
        - allocateLocal() now allocates large objects into the local
          nursery, rather than taking a global lock and allocating
          then in gen 0 step 0.
      
        - allocatePinned() was still allocating from global storage and
          taking a lock each time, now it uses local storage. 
          (mallocForeignPtrBytes should be faster with -threaded).
          
        - We had a gen 0 step 0, distinct from the nurseries, which are
          stored in a separate nurseries[] array.  This is slightly strange.
          I removed the g0s0 global that pointed to gen 0 step 0, and
          removed all uses of it.  I think now we don't use gen 0 step 0 at
          all, except possibly when there is only one generation.  Possibly
          more tidying up is needed here.
      
        - I removed the global allocate() function, and renamed
          allocateLocal() to allocate().
      
        - the alloc_blocks global is gone.  MAYBE_GC() and
          doYouWantToGC() now check the local nursery only.
      5270423a
  5. 02 Aug, 2009 1 commit
    • Simon Marlow's avatar
      RTS tidyup sweep, first phase · a2a67cd5
      Simon Marlow authored
      The first phase of this tidyup is focussed on the header files, and in
      particular making sure we are exposinng publicly exactly what we need
      to, and no more.
      
       - Rts.h now includes everything that the RTS exposes publicly,
         rather than a random subset of it.
      
       - Most of the public header files have moved into subdirectories, and
         many of them have been renamed.  But clients should not need to
         include any of the other headers directly, just #include the main
         public headers: Rts.h, HsFFI.h, RtsAPI.h.
      
       - All the headers needed for via-C compilation have moved into the
         stg subdirectory, which is self-contained.  Most of the headers for
         the rest of the RTS APIs have moved into the rts subdirectory.
      
       - I left MachDeps.h where it is, because it is so widely used in
         Haskell code.
       
       - I left a deprecated stub for RtsFlags.h in place.  The flag
         structures are now exposed by Rts.h.
      
       - Various internal APIs are no longer exposed by public header files.
      
       - Various bits of dead code and declarations have been removed
      
       - More gcc warnings are turned on, and the RTS code is more
         warning-clean.
      
       - More source files #include "PosixSource.h", and hence only use
         standard POSIX (1003.1c-1995) interfaces.
      
      There is a lot more tidying up still to do, this is just the first
      pass.  I also intend to standardise the names for external RTS APIs
      (e.g use the rts_ prefix consistently), and declare the internal APIs
      as hidden for shared libraries.
      a2a67cd5
  6. 14 Jan, 2009 1 commit
    • Simon Marlow's avatar
      Detect when a C finalizer calls back to Haskell · 348e8f80
      Simon Marlow authored
      This is illegal now, after the fix for #1364, but it turns out that
      the existing check for dodgy callbacks doesn't catch finalizers
      calling back, so we need another test.  This will be particularly
      important for 6.10.2, because the behaviour has changed.
      348e8f80
  7. 10 Dec, 2008 1 commit
  8. 06 Aug, 2007 1 commit
  9. 15 Nov, 2006 1 commit
  10. 08 Jun, 2006 1 commit
    • Simon Marlow's avatar
      New tracing interface · 5a2769f0
      Simon Marlow authored
      A simple interface for generating trace messages with timestamps and
      thread IDs attached to them.  Most debugging output goes through this
      interface now, so it is straightforward to get timestamped debugging
      traces with +RTS -vt.  Also, we plan to use this to generate
      parallelism profiles from the trace output.
      5a2769f0
  11. 07 Apr, 2006 1 commit
    • Simon Marlow's avatar
      Reorganisation of the source tree · 0065d5ab
      Simon Marlow authored
      Most of the other users of the fptools build system have migrated to
      Cabal, and with the move to darcs we can now flatten the source tree
      without losing history, so here goes.
      
      The main change is that the ghc/ subdir is gone, and most of what it
      contained is now at the top level.  The build system now makes no
      pretense at being multi-project, it is just the GHC build system.
      
      No doubt this will break many things, and there will be a period of
      instability while we fix the dependencies.  A straightforward build
      should work, but I haven't yet fixed binary/source distributions.
      Changes to the Building Guide will follow, too.
      0065d5ab
  12. 21 Oct, 2005 1 commit
    • simonmar's avatar
      [project @ 2005-10-21 14:02:17 by simonmar] · 03a9ff01
      simonmar authored
      Big re-hash of the threaded/SMP runtime
      
      This is a significant reworking of the threaded and SMP parts of
      the runtime.  There are two overall goals here:
      
        - To push down the scheduler lock, reducing contention and allowing
          more parts of the system to run without locks.  In particular,
          the scheduler does not require a lock any more in the common case.
      
        - To improve affinity, so that running Haskell threads stick to the
          same OS threads as much as possible.
      
      At this point we have the basic structure working, but there are some
      pieces missing.  I believe it's reasonably stable - the important
      parts of the testsuite pass in all the (normal,threaded,SMP) ways.
      
      In more detail:
      
        - Each capability now has a run queue, instead of one global run
          queue.  The Capability and Task APIs have been completely
          rewritten; see Capability.h and Task.h for the details.
      
        - Each capability has its own pool of worker Tasks.  Hence, Haskell
          threads on a Capability's run queue will run on the same worker
          Task(s).  As long as the OS is doing something reasonable, this
          should mean they usually stick to the same CPU.  Another way to
          look at this is that we're assuming each Capability is associated
          with a fixed CPU.
      
        - What used to be StgMainThread is now part of the Task structure.
          Every OS thread in the runtime has an associated Task, and it
          can ask for its current Task at any time with myTask().
      
        - removed RTS_SUPPORTS_THREADS symbol, use THREADED_RTS instead
          (it is now defined for SMP too).
      
        - The RtsAPI has had to change; we must explicitly pass a Capability
          around now.  The previous interface assumed some global state.
          SchedAPI has also changed a lot.
      
        - The OSThreads API now supports thread-local storage, used to
          implement myTask(), although it could be done more efficiently
          using gcc's __thread extension when available.
      
        - I've moved some POSIX-specific stuff into the posix subdirectory,
          moving in the direction of separating out platform-specific
          implementations.
      
        - lots of lock-debugging and assertions in the runtime.  In particular,
          when DEBUG is on, we catch multiple ACQUIRE_LOCK()s, and there is
          also an ASSERT_LOCK_HELD() call.
      
      What's missing so far:
      
        - I have almost certainly broken the Win32 build, will fix soon.
      
        - any kind of thread migration or load balancing.  This is high up
          the agenda, though.
      
        - various performance tweaks to do
      
        - throwTo and forkProcess still do not work in SMP mode
      03a9ff01
  13. 10 Feb, 2005 1 commit
    • simonmar's avatar
      [project @ 2005-02-10 13:01:52 by simonmar] · e7c3f957
      simonmar authored
      GC changes: instead of threading old-generation mutable lists
      through objects in the heap, keep it in a separate flat array.
      
      This has some advantages:
      
        - the IND_OLDGEN object is now only 2 words, so the minimum
          size of a THUNK is now 2 words instead of 3.  This saves
          some amount of allocation (about 2% on average according to
          my measurements), and is more friendly to the cache by
          squashing objects together more.
      
        - keeping the mutable list separate from the IND object
          will be necessary for our multiprocessor implementation.
      
        - removing the mut_link field makes the layout of some objects
          more uniform, leading to less complexity and special cases.
      
        - I also unified the two mutable lists (mut_once_list and mut_list)
          into a single mutable list, which lead to more simplifications
          in the GC.
      e7c3f957
  14. 21 Jan, 2005 1 commit
    • simonmar's avatar
      [project @ 2005-01-21 16:02:47 by simonmar] · 3f205c43
      simonmar authored
      Don't try to run finalizers at program exit.  This turned out to be
      hard if not impossible to do in general, so now we don't attempt it at
      all.
      
      The Main.main wrapper, previously called runIO and now called
      runMainIO, flushes stdout and stderr before exiting.  This should
      catch most cases where programs rely on Handles being flushed at
      program exit, but note that now if you simply drop a Handle in your
      program, there's no guarantee it'll be flushed on exit.  If the
      punters complain enough, I suppose we could implement a global
      Handle table and flush them all at exit... I'd rather not do this if
      possible, though.  Better to teach people to close their Handles
      properly.
      3f205c43
  15. 12 Sep, 2004 1 commit
  16. 03 Sep, 2004 1 commit
    • simonmar's avatar
      [project @ 2004-09-03 15:28:18 by simonmar] · 95ca6bff
      simonmar authored
      Cleanup: all (well, most) messages from the RTS now go through the
      functions in RtsUtils: barf(), debugBelch() and errorBelch().  The
      latter two were previously called belch() and prog_belch()
      respectively.  See the comments for the right usage of these message
      functions.
      
      One reason for doing this is so that we can avoid spurious uses of
      stdout/stderr by Haskell apps on platforms where we shouldn't be using
      them (eg. non-console apps on Windows).
      95ca6bff
  17. 13 Aug, 2004 1 commit
  18. 24 Oct, 2003 1 commit
  19. 21 Sep, 2003 1 commit
    • wolfgang's avatar
      [project @ 2003-09-21 22:20:51 by wolfgang] · 85aa72b9
      wolfgang authored
      Bound Threads
      =============
      
      Introduce a way to use foreign libraries that rely on thread local state
      from multiple threads (mainly affects the threaded RTS).
      
      See the file threads.tex in CVS at haskell-report/ffi/threads.tex
      (not entirely finished yet) for a definition of this extension. A less formal
      description is also found in the documentation of Control.Concurrent.
      
      The changes mostly affect the THREADED_RTS (./configure --enable-threaded-rts),
      except for saving & restoring errno on a per-TSO basis, which is also necessary
      for the non-threaded RTS (a bugfix).
      
      Detailed list of changes
      ------------------------
      
      - errno is saved in the TSO object and restored when necessary:
      ghc/includes/TSO.h, ghc/rts/Interpreter.c, ghc/rts/Schedule.c
      
      - rts_mainLazyIO is no longer needed, main is no special case anymore
      ghc/includes/RtsAPI.h, ghc/rts/RtsAPI.c, ghc/rts/Main.c, ghc/rts/Weak.c
      
      - passCapability: a new function that releases the capability and "passes"
        it to a specific OS thread:
      ghc/rts/Capability.h ghc/rts/Capability.c
      
      - waitThread(), scheduleWaitThread() and schedule() get an optional
        Capability *initialCapability passed as an argument:
      ghc/includes/SchedAPI.h, ghc/rts/Schedule.c, ghc/rts/RtsAPI.c
      
      - Bound Thread scheduling (that's what this is all about):
      ghc/rts/Schedule.h, ghc/rts/Schedule.c
      
      - new Primop isCurrentThreadBound#:
      ghc/compiler/prelude/primops.txt.pp, ghc/includes/PrimOps.h, ghc/rts/PrimOps.hc,
      ghc/rts/Schedule.h, ghc/rts/Schedule.c
      
      - a simple function, rtsSupportsBoundThreads, that returns true if THREADED_RTS
        is defined:
      ghc/rts/Schedule.h, ghc/rts/Schedule.c
      
      - a new implementation of forkProcess (the old implementation stays in place
        for the non-threaded case). Partially broken; works for the standard
        fork-and-exec case, but not for much else. A proper forkProcess is
        really next to impossible to implement:
      ghc/rts/Schedule.c
      
      - Library support for bound threads:
          Control.Concurrent.
            rtsSupportsBoundThreads, isCurrentThreadBound, forkOS,
            runInBoundThread, runInUnboundThread
      libraries/base/Control/Concurrent.hs, libraries/base/Makefile,
      libraries/base/include/HsBase.h, libraries/base/cbits/forkOS.c (new file)
      85aa72b9
  20. 26 Mar, 2003 1 commit
  21. 17 Mar, 2003 1 commit
    • simonmar's avatar
      [project @ 2003-03-17 14:47:47 by simonmar] · 74b46a5d
      simonmar authored
      Haskell quiz:  what should this program do?
      
        main = return undefined
      
      answer: run to completion and exit successfully.  GHC erroneously
      evaluates the returned value from main, which causes this example to
      fail with an uncaught exception (the evaluation is even done outside
      of the main exception handler!).
      74b46a5d
  22. 25 Jan, 2003 1 commit
    • wolfgang's avatar
      [project @ 2003-01-25 15:54:48 by wolfgang] · af136096
      wolfgang authored
      This commit fixes many bugs and limitations in the threaded RTS.
      There are still some issues remaining, though.
      
      The following bugs should have been fixed:
      
      - [+] "safe" calls could cause crashes
      - [+] yieldToReturningWorker/grabReturnCapability
          -     It used to deadlock.
      - [+] couldn't wake blocked workers
          -     Calls into the RTS could go unanswered for a long time, and
                that includes ordinary callbacks in some circumstances.
      - [+] couldn't block on an MVar and expect to be woken up by a signal
            handler
          -     Depending on the exact situation, the RTS shut down or
                blocked forever and ignored the signal.
      - [+] The locking scheme in RtsAPI.c didn't work
      - [+] run_thread label in wrong place (schedule())
      - [+] Deadlock in GHC.Handle
          -     if a signal arrived at the wrong time, an mvar was never
                filled again
      - [+] Signals delivered to the "wrong" thread were ignored or handled
            too late.
      
      Issues:
      *) If GC can move TSO objects (I don't know - can it?), then ghci
      will occasionally crash when calling foreign functions, because the
      parameters are stored on the TSO stack.
      
      *) There is still a race condition lurking in the code
      (both threaded and non-threaded RTS are affected):
      If a signal arrives after the check for pending signals in
      schedule(), but before the call to select() in awaitEvent(),
      select() will be called anyway. The signal handler will be
      executed much later than expected.
      
      *) For Win32, GHC doesn't yet support non-blocking IO, so while a
      thread is waiting for IO, no call-ins can happen. If the RTS is
      blocked in awaitEvent, it uses a polling loop on Win32, so call-ins
      should work (although the polling loop looks ugly).
      
      *) Deadlock detection is disabled for the threaded rts, because I
      don't know how to do it properly in the presence of foreign call-ins
      from foreign threads.
      This causes the tests conc031, conc033 and conc034 to fail.
      
      *) "safe" is currently treated as "threadsafe". Implementing "safe" in
      a way that blocks other Haskell threads is more difficult than was
      thought at first. I think it could be done with a few additional lines
      of code, but personally, I'm strongly in favour of abolishing the
      distinction.
      
      *) Running finalizers at program termination is inefficient - there
      are two OS threads passing messages back and forth for every finalizer
      that is run. Also (just as in the non-threaded case) the finalizers
      are run in parallel to any remaining haskell threads and to any
      foreign call-ins that might still happen.
      af136096
  23. 11 Dec, 2002 1 commit
    • simonmar's avatar
      [project @ 2002-12-11 15:36:20 by simonmar] · 0bffc410
      simonmar authored
      Merge the eval-apply-branch on to the HEAD
      ------------------------------------------
      
      This is a change to GHC's evaluation model in order to ultimately make
      GHC more portable and to reduce complexity in some areas.
      
      At some point we'll update the commentary to describe the new state of
      the RTS.  Pending that, the highlights of this change are:
      
        - No more Su.  The Su register is gone, update frames are one
          word smaller.
      
        - Slow-entry points and arg checks are gone.  Unknown function calls
          are handled by automatically-generated RTS entry points (AutoApply.hc,
          generated by the program in utils/genapply).
      
        - The stack layout is stricter: there are no "pending arguments" on
          the stack any more, the stack is always strictly a sequence of
          stack frames.
      
          This means that there's no need for LOOKS_LIKE_GHC_INFO() or
          LOOKS_LIKE_STATIC_CLOSURE() any more, and GHC doesn't need to know
          how to find the boundary between the text and data segments (BIG WIN!).
      
        - A couple of nasty hacks in the mangler caused by the neet to
          identify closure ptrs vs. info tables have gone away.
      
        - Info tables are a bit more complicated.  See InfoTables.h for the
          details.
      
        - As a side effect, GHCi can now deal with polymorphic seq.  Some bugs
          in GHCi which affected primitives and unboxed tuples are now
          fixed.
      
        - Binary sizes are reduced by about 7% on x86.  Performance is roughly
          similar, some programs get faster while some get slower.  I've seen
          GHCi perform worse on some examples, but haven't investigated
          further yet (GHCi performance *should* be about the same or better
          in theory).
      
        - Internally the code generator is rather better organised.  I've moved
          info-table generation from the NCG into the main codeGen where it is
          shared with the C back-end; info tables are now emitted as arrays
          of words in both back-ends.  The NCG is one step closer to being able
          to support profiling.
      
      This has all been fairly thoroughly tested, but no doubt I've messed
      up the commit in some way.
      0bffc410
  24. 19 Jun, 2002 1 commit
  25. 13 Jun, 2002 1 commit
  26. 26 Apr, 2002 1 commit
  27. 19 Apr, 2002 1 commit
  28. 18 Feb, 2002 1 commit
    • sof's avatar
      [project @ 2002-02-18 13:26:12 by sof] · 6e2ea06c
      sof authored
      Be clear about the lock assumptions of GarbageCollect(); it
      is now required to hold sched_mutex.
      
      The real reason for adding this requirement is so that when
      prior to scheduling finalizers and doing thread resurrection,
      GarbageCollect() may set the lock status of sched_mutex to
      the state expected by scheduleFinalizers() and resurrectThreads()
      (i.e., unlocked).
      
      Note: this is only an issue with pthreads. In the Win32 threading
      model, it's a NOP for a thread to grab a mutex it already holds.
      6e2ea06c
  29. 26 Nov, 2001 1 commit
    • simonmar's avatar
      [project @ 2001-11-26 16:54:21 by simonmar] · dbef766c
      simonmar authored
      Profiling cleanup.
      
      This commit eliminates some duplication in the various heap profiling
      subsystems, and generally centralises much of the machinery.  The key
      concept is the separation of a heap *census* (which is now done in one
      place only instead of three) from the calculation of retainer sets.
      Previously the retainer profiling code also did a heap census on the
      fly, and lag-drag-void profiling had its own census machinery.
      
      Value-adds:
      
         - you can now restrict a heap profile to certain retainer sets,
           but still display by cost centre (or type, or closure or
           whatever).
      
         - I've added an option to restrict the maximum retainer set size
           (+RTS -R<size>, defaulting to 8).
      
         - I've cleaned up the heap profiling options at the request of
           Simon PJ.  See the help text for details.  The new scheme
           is backwards compatible with the old.
      
         - I've removed some odd bits of LDV or retainer profiling-specific
           code from various parts of the system.
      
         - the time taken doing heap censuses (and retainer set calculation)
           is now accurately reported by the RTS when you say +RTS -Sstderr.
      
      Still to come:
      
         - restricting a profile to a particular biography
           (lag/drag/void/use).  This requires keeping old heap censuses
           around, but the infrastructure is now in place to do this.
      dbef766c
  30. 22 Nov, 2001 1 commit
    • simonmar's avatar
      [project @ 2001-11-22 14:25:11 by simonmar] · db61851c
      simonmar authored
      Retainer Profiling / Lag-drag-void profiling.
      
      This is mostly work by Sungwoo Park, who spent a summer internship at
      MSR Cambridge this year implementing these two types of heap profiling
      in GHC.
      
      Relative to Sungwoo's original work, I've made some improvements to
      the code:
      
         - it's now possible to apply constraints to retainer and LDV profiles
           in the same way as we do for other types of heap profile (eg.
           +RTS -hc{foo,bar} -hR -RTS gives you a retainer profiling considering
           only closures with cost centres 'foo' and 'bar').
      
         - the heap-profile timer implementation is cleaned up.
      
         - heap profiling no longer has to be run in a two-space heap.
      
         - general cleanup of the code and application of the SDM C coding
           style guidelines.
      
      Profiling will be a little slower and require more space than before,
      mainly because closures have an extra header word to support either
      retainer profiling or LDV profiling (you can't do both at the same
      time).
      
      We've used the new profiling tools on GHC itself, with moderate
      success.  Fixes for some space leaks in GHC to follow...
      db61851c
  31. 14 Aug, 2001 1 commit
    • sewardj's avatar
      [project @ 2001-08-14 13:40:07 by sewardj] · bc5c8021
      sewardj authored
      Change the story about POSIX headers in C compilation.
      
      Until now, all C code in the RTS and library cbits has by default been
      compiled with settings for POSIXness enabled, that is:
         #define _POSIX_SOURCE   1
         #define _POSIX_C_SOURCE 199309L
         #define _ISOC9X_SOURCE
      If you wanted to negate this, you'd have to define NON_POSIX_SOURCE
      before including headers.
      
      This scheme has some bad effects:
      
      * It means that ccall-unfoldings exported via interfaces from a
        module compiled with -DNON_POSIX_SOURCE may not compile when
        imported into a module which does not -DNON_POSIX_SOURCE.
      
      * It overlaps with the feature tests we do with autoconf.
      
      * It seems to have caused borkage in the Solaris builds for some
        considerable period of time.
      
      The New Way is:
      
      * The default changes to not-being-in-Posix mode.
      
      * If you want to force a C file into Posix mode, #include as
        the **first** include the new file ghc/includes/PosixSource.h.
        Most of the RTS C sources have this include now.
      
      * NON_POSIX_SOURCE is almost totally expunged.  Unfortunately
        we have to retain some vestiges of it in ghc/compiler so that
        modules compiled via C on Solaris using older compilers don't
        break.
      bc5c8021
  32. 04 Dec, 2000 1 commit
  33. 13 Nov, 2000 1 commit
  34. 20 Jun, 2000 1 commit
    • simonmar's avatar
      [project @ 2000-06-20 15:18:40 by simonmar] · 853cec45
      simonmar authored
      Don't try to finalize DEAD_WEAKs.  This fix has been sitting in my
      tree for so long, I can't remember whether it was a real bugfix or
      just a cleanup, oh well.
      853cec45
  35. 22 May, 2000 1 commit
    • simonmar's avatar
      [project @ 2000-05-22 13:09:29 by simonmar] · d3058014
      simonmar authored
      Batch finalizers on a per-GC basis.  That is, after a GC a single
      thread is created to run the pending finalizers, rather than creating
      a thread for each finalizer.
      
      This is almost as fast as having a global thread to run finalizers,
      but doesn't require any global state or special treatment by the
      scheduler.
      d3058014
  36. 25 Feb, 2000 1 commit
  37. 10 Dec, 1999 1 commit
  38. 06 Jul, 1999 1 commit
  39. 26 Feb, 1999 2 commits