[libcds.git] / change.log

2.4.0

2.3.0 31.07.2017
    General release
    - Changed: cds::gc::HP is totally refactored:
        - simplified internal structures;
        - added ability to specify an external allocator for internal data;
        - external API for gc::HP is slightly changed: now scan type
          cannot be changed on the fly; it can be specified only in
          construction time.
    - Changed: cds::gc::DHP is totally refactored to overcome some internal
      limitations. Now gc::DHP is fully adaptive variant of Hazard Pointer 
      SMR, any dependencies on count of thread are removed, count of retired
      data and hazard pointers per thread are increased automaticaly by perforce.
      External API of gc::DHP class is changed: now only initial count 
      of hazard pointers can be specified in the constructor. Like new gc::HP,
      the new gc::DHP supports an external allocator.
    - Changed: exception handling. Now, exceptions raise by invoking new 
      cds::throw_exception() function. If you compile your code with exception disabled,
      the function prints an exception message to stdout and calls abort()
      instead of throwing.
    - Flat Combining: fixed memory-order bug that can lead to crash on weak ordered
      architecture like PowerPC or ARM
    - Added: erase_at( iterator ) function to MichaelHashSet/Map and SplitListSet/Map
      based on IterableList
    - Fixed a bug in BronsonAVLTreeMap::extract_min()/extract_max()/clear().
    - Removed: signal-handled threaded uRCU (cds::urcu::signal_threaded) due
      bad performance
    - Added more flat-combining queue tests, thanks to Marsel Galimullin.
    - Changed cmake scripts to support MacOS and ARMv7/ARMv8 (64 bit),
      thanks to Michail Komarov (https://github.com/Nemo1369)
    - Stress tests: removed command line parameter --detail-level and
      envvar CDSTEST_DETAIL_LEVEL for reducing compile time and executable size.
      To make full testset compile libcds with -DCDS_STRESS_TEST_LEVEL=N where
      N is 1 or 2.
    - Changed: refactoring cds::backoff::exponential and cds::backoff::delay
      back-off strategies to avoid static data members in template classes. 
    - The library is extensively tested on x86-64, PowerPC and AArch64,
      thanks to GCC Compile Farm project
 
2.2.0 04.01.2017
    General release
    - Changed: CMake is used for build libcds. Ancient build.sh has been removed
    - Changed: unit and stress tests are migrated to googletest framework
    - Added: IterableList - an implementation of ordered list with 
      thread-safe iterator. MichaelSet/Map and SplitListSet/Map support 
      this type of ordered list and thread-safe iterable too.
    - Added: wait strategies for flat combining technique. Based on
      research by Marsel Galimullin and Nikolai Rapotkin.
    - Fixed: SkipList erase() and find() bugs that cause to infinite loop 
      or to program crash in rare case.
    - Fixed: serious bug in MichaelSet::emplace() function
      New node was created twice from the arguments by move semantics. 
      However, move semantics may change internal state of the argument
      that can lead to an incorrect element and even an incorrect key
      that breaks the set logic.
    - Fixed: bug in FeldmanHashSet::erase_at( iterator ): due an error
      in precondition checking the function may incorrectly return false.
    - Fixed: possible double-free case in flat combining algorithm. 
      Thanks to Amila Jayasekara who pointed me to this problem
    - Changed: cds::opt::buffer option is divided to initialized
      (cds::opt::v::initialized_dynamic_buffer, cds::opt::v::initialized_static_buffer)
      and uninitialized (cds::opt::v::uninitialized_dynamic_buffer, cds::opt::v::uninitialized_static_buffer)
      ones. The old cds::opt::v::dynamic_buffer and cds::opt::v::static_buffer classes
      are removed.
    - Removed: TsigasCysleQueue (due undecidable ABA-problem)
    - Removed: Michael's allocator cds/memory/michael/allocator.h
    - Fixed: use-after-free bug in VyukovMPMCCycleQueue internal buffer.
      To prevent this bug the queue uses an uninitialized buffer now.
    - Fixed: rare priority inversion bug in MSPriorityQueue
    - Added: for minimizing runtime of stress test the detail level for some test is added.
      Command line argument --detail-level=N specifies what test should be ran: each
      test with level not greater than N will be ran. Instead of command line arg
      the enviromnent variable CDSTEST_DETAIL_LEVEL=N may be used.
      By default, the detail level is 0 that means only limited set of the test will be ran.

2.1.0 06.01.2016
    General release
    - Added: FeldmanHashSet/Map - an interesting hash map algorithm
      based on multi-level array, requires perfect hashing or fixed-sized keys.
      Supports thread-safe bidirectional iterators.
    - Added: BronsonAVLTreeMap - Bronson's et al AVL tree implementation
    - Added: CMake build script, thanks to Eugeny Kalishenko
    - Changed: SplitList performance improving, thanks to Mike Krinkin
    - Changed: semantic of member functions extract(), get() and its
      variants for MichaelList RCU-based specialization: extract() does not
      require RCU locking, get() now returns special wrapper object of type raw_ptr,
      see doc.
      Thus, semantics of extract()/get() of all RCU-based set and maps based on 
      MichaelList (MichaelSet/Map, SplitListSet/Map) has been changed too.
    - Changed: SplitListSet/Map functions get() and get_with() return special wrapper
      object of type raw_ptr, see doc.
    - Removed: SplitListSet/Map force_dispose() function.
    - cds::lock namespace is renamed to cds::sync. All classes defined in cds::lock namespace 
      are moved to cds::sync with new names (for example, cds::lock::SpinLock is renamed to
      cds::sync::spin_lock). cds::lock namespace and its contents is deprecated, it is kept 
      for backward compatibility.
    - The library has been checked by ThreadSanitizer, a lot of bugs has been fixed
    - Added support for clang 3.7 with libc++

2.0.0 30.12.2014
    General release
    - the library has been rewritten to support at least C++11. Compilers: GCC 4.8+, clang 3.3+, 
      MS Visual C++ 12 (2013) Update 4 an above.
    - Removed: MichaelDeque, reason: the implementation is heavy-weighted, inefficient,
      and, seems, unstable.
    - Removed: cds::gc::HRC garbage collector, reason: the implementation is inefficient 
      and unstable.
    - Changed: all container's declaration except StripedSet has been unified to the
      following traits-based form: 
           class Container< GC, T, Traits >
    - Added: new member function pop_with(Func) to cds::container::TreiberStack
    - Added: new member functions enqueue_with(Func), dequeue_with(Func) to 
             cds::container::MSQueue
             cds::container::MoirQueue
             cds::container::BasketQueue
             cds::container::OptimisticQueue
             cds::container::RWQueue
             cds::container::SegmentedQueue
             cds::container::TsigasCycleQueue
             cds::container::VyukovMPMCCycleQueue
    - Added: new member functions push_with(Func) and pop_with(Func) to cds::container::MSPriorityQueue
    - SegmentedQueue: add padding into segmented_queue::traits to eliminate false sharing.
    - Changed: guarded_ptr and exempt_ptr have move semantics now. The container's extract() and get()
      member functions return the objects of that type.
    - Changed: improved cds::gc::HP and cds::gc::DHP internal implementation
    - Changed: map member function insert_key() has been renamed to insert_with()
    - Changed: cds/cxx11_atomic.h has been renamed to cds/algo/atomic.h
    - Removed: cds/refcounter.h

1.6.0 23.09.2014
    General release
    - Add flat combining (FC) technique and FC-based containers: FCStack, FCQueue, 
      FCDeque, FCPriorityQueue
    - Add elimination back-off feature to TreiberStack class
    - Add SegmentedQueue - an unfair queue implementation
    - New member functions for sets and maps:
      Functions get() and get_with() search a key and return the pointer to item found 
      in safe manner.
      Function extract() searches a key, unlinks the item found from the container 
      and returns pointer to item in safe manner.
      The functions get, get_with, extract, extract_with extract_min, extract_max 
      has been added to the following container:
        SkipListSet, SkipListMap
        EllenBinTree, EllenBinTreeSet, EllenBinTreeMap
      The functions get, get_with, extract, extract_with has been added 
      to the following container:
        MichaelList, LazyList
        MichaelHashSet, MichaelHashMap
        SplitListSet, SplitListMap
    - Fix a serious bug in cds::gc::HRC
    - Changed MSPriorityQueue to simplify interface and to fix possible pop() deadlock
    - Fix a bug in BasketQueue
    - Fix EllenBinTree crash under high contention
    - Changed: the thread manager detach order to prevent crashing of signal-handled RCU
      in some case.
    - Changed: cds::gc::HP calls Scan() when a thread is detached.
      This prevents accumulating retired data.
    - Changed: minimal boost version is 1.51
    - Removed: file cds/lock/rwlock.h

1.5.0 29.12.2013
    General release
    1. Added: EllenBinTree - an implementation of unbalanced binary search
      tree based on paper [2010] F.Ellen, P.Fatourou, E.Ruppert, F.van Breugel 
      "Non-blocking Binary Search Tree".
    2. Added: MSPriorityQueue - an array-based lock-based priority queue heap, 
      see [1996] G.Hunt, M.Michael, S. Parthasarathy, M.Scott "An efficient 
      algorithm for concurrent priority queue heaps"
    3. Added support for boost.atomic for boost 1.54 and above. 
      Now, libcds supports processor architecture like ARM, PowerPC and any other
      that are supported by boost.atomic or by C++11 compiler. Any feedbacks are appreciated.
      To use boost.atomic you should specify -DCDS_USE_BOOST_ATOMIC in compiler's command line.
    4. Added: a new CDS_USE_LIBCDS_ATOMIC preprocessor flag has been added to direct
      the compiler to use libcds atomic unconditionally.
    5. build.sh has been modified to relax processor architecture and OS requirements. 
      This allows to use libcds with native compiler atomic support (or boost.atomic) 
      for a processor architecture that has not been tested by libcds's developers.
    6. Added support for CLang 3.3
    7. Added support for MS VC++ 2013
    8. Added support for Mac OS X, see build/sample/build-osx-clang-libc++.sh, 
      build/sample/build-osx-gcc.sh for example.
    9. Fixed: SkipListSet::erase_with does not take into account "less" predicate parameter.
    10.Fixed: some bugs in SkipListSet leading to deadloop
    11.Fixed: MichaelMap bug: computing hash value for type Q different from key type.

1.4.0 20.05.2013
    General release
    1. Added: user-space RCU garbage collector (5 different implementations), 
       see cds::urcu namespace
    2. Added: RCU-related set/map container specializations
    3. Added: Skip-list specialization for cds::gc::nogc (undeletable skip-list)
    4. For set/map classes: find_with and erase_with member functions have been added.
       These functions allow to use different predicates for searching.
    5. Added: threading model based on Ñ++11 thread_local keyword (CDS_THREADING_CXX11).
       At present, only gcc 4.8 supports such model.
    6. Fixed: bug #11 "ABA bug in libcds 1.3.1 cds/intrusive/msqueue.h"
       Thanks to Jelle van den Hooff.
    7. Added support for GCC 4.8

1.3.1 27.01.2013
    Bugfix release
    - Bug fixed: building libcds with boost versions before 1.48
      Thanks Lucas Larsch who points me to this problem.
  
1.3.0 29.12.2012
    General release
    1. Added: StripedSet, StripedMap - hash set and hash map 
        implementation based on fine-grained lock-striping technique
    2. Added: CuckooSet, CuckooMap - implementation of cuckoo hashing algorithm
        based on fine-grained lock-striping technique
    3. Added: SkipListSet, SkipListMap - implementation of lock-free skip list
    4. Added: template <typename... Args> emplace(Args&&... args) member function 
        for all containers in cds::container namespace. This function is available 
        only if the compiler supports new C++11 features - variadic
        templates and move semantics.
    5. Changed: lambda functions are used internally instead of wrapping functors.
        If the compiler does not support C++11 lambdas the old-style wrapping functors are used.
    6. Changed: test projects has been splitted for optimizing compile time.
    7. Breaking change: class cds::lock::Auto has been renamed to cds::lock::scoped_lock,
        class cds::lock::AutoUnlock has been removed
    8. Added: support for MinGW (tested with TDM-GCC 64bit, gcc 4.7)
    
1.2.0 20.08.2012 (beta)
    General release
    1. Added: MichaelDeque - deque lock-free algo discovered by Maged Michael
    2. Added: BasketQueue - Michael's queue modification discovered by Nir Shavit et al.
    3. Added: support of Clang 3.0, 3.1 compiler (tested on Linux with boost 1.49)
    4. Fixed: solving problem of 8-byte atomic data alignment on 32-bit platforms
    5. Fixed bug 3536393: OptimisticQueue core dump 

1.1.0 17.04.2012 (beta)
    General release
    1. Added: C++11 atomic operations support. The library has been rewritten
        for using std::atomic class and operations proposed in C++11 Standard.
        If the compiler does not support the standard <atomic> library, 
        own partial implementation declared in cds/cxx11_atomic.h is used. 
        cxx11_atomic.h contains implementation for lock-free part of C++11 
        <atomic> header needed for libcds.
    2. Added: support for C++11 feature (if applicable):
       - inline namespace (for GCC 4.4+)
       - function =default and =delete specifiers (for GCC 4.4+)
    3. Changed: the main reclamation cycle ("liberate" function) of cds::gc::PTB 
       memory reclamation schema has been optimized. Previous implementation
       could lead to unbounded memory consumption under high contention.
    4. Changed: the internal structure of cds::intrusive::OptimisticQueue is greatly simplified. 
       The interface of the class is slightly changed.
    5. Fixed: some problem with cds::gc::HRC memory reclamation schema that
       could be the cause of occasional program crash.
    6. Fixed: an error in node reclamation algo in queue implementation (MSQueue, MoirQueue, 
       OptimisticQueue). As an result of the error, some items could be lost with memory leaks.
    7. Changed: cds::concept namespace and its content has been removed
    8. Added support for Microsoft Visual C++ 11 Beta
    9. Added support for GCC 4.7
    
1.0.0  31.12.2011 (beta)
    This version is completely rewritten to support intrusive version of lock-free containers
    and more lightweight garbage collectors interface.
    The class hierarchy and interfaces have been completely reimplemented from scratch.

    1. Added: intrusive containers. Many lock-free containers in libcds have the intrusive
       counterparts. The library is fully refactored to support intrusive containers.
       Class hierarchy is changed: almost all non-intrusive container classes are based 
       on their intrusive versions.
       Two new namespace is added:
        cds::intrusive - for intrusive containers
        cds::container - for non-intrusive containers
       Namespaces by container type (cds::queue, cds::map and so on) have been removed.
    2. Added: New option-based approach is used for class declaration instead
       old traits-based one. This approach allows to declare template arguments
       in position-independent manner that is very useful for complex template declarations.
       Option-based declarations use C++0x variadic templates if compiler supports it (GCC),
       otherwise (MS VC) an emulation is used.
    3. Changed: garbage collectors interface is generalized. cds::gc::GC (where GC is
       one of HP, HRC, PTB) classes has been added.
    4. Removed: tagged pointer GC. This GC
       - unsafe for complex data structure
       - x86-specific since it requires double-width CAS primitive
       - memory-consuming since it requires separate free-list for each type stored in the containers
    5. Default threading model is changed (see doc for cds::threading namespace):
       - for Windows and MSVC++, CDS_THREADING_WIN_TLS is the default now
       - for *nix and GCC, CDS_THREADING_PTHREAD is the default now
    6. Added GCC 4.6 support (constexpr)
    7. Added Microsoft Visual Studio 2010 (vc10) solution

0.8.0  28.03.2011 (beta)
    1. Added: cds::Initialize and cds::Terminate functions that initializes and frees library's
       internal structures.
    2. Added: cds::memory::michael::Heap - Michael's lock-free allocator
    3. Added: Exponential back-off strategy for spinning
    4. Added: cds::queue::vyukov_mpmc_bounded - bounded queue
       developed by Dmitry Vyukov (http://www.1024cores.net)
    5. Added: support for FreeBSD amd64, x86

0.7.2  27.02.2011 (beta)
    1. [Bug 3157201] Added implementation of threading manager based on Windows TLS API, see
       cds::threading::wintls::Manager. Added CDS_THREADING_WIN_TLS macro. See docs for
       cds::threading namespace for details.
    2. Fixed bug in cds::threading::pthread::Manager: ptb_gc has not been initialized properly.
    3. New function
            template <typename T, typename FUNC>
            bool erase( const key_type& key, T& dest, FUNC func ) ;
       has been added to all map classes.
    4. New function
            template <typename T, typename FUNC>
            bool insert( const key_type& key, T& val, FUNC func ) ;
       has been added to all map classes.
    5. Added new argument "bNew" to functor "func" of map's "ensure" member function:
            void func( VALUE& itemValue, const VALUE& val, bool bNew ) ;
        bNew = true if new item has been added
        bNew = false if key is found
    6. Fixed bug in cds::map::SplitOrderedList: LSB of dummy node's hash should be zero
    7. Changed: thread liveliness checking on *nix has been changed to pthread_kill(id, 0).
    8. Fixed: in map template member functions the functor may be passed by value
       or by reference; use boost::ref( yourFunctor ) to pass your functor by reference
    9. Fixed: cds::gc::tagged GC and all classes based on this GC has been rewritten
       to solve stability problems.

0.7.1  30.12.2010 (beta)
    1. [Bug 3130852] cds::queue::TZCyclicQueue::empty() has been corrected
    2. [Bug 3128161] It seems, GCC 4.4 has a bug in __thread on x86 and x86_64. New "threading model"
       CDS_THREADING_AUTODETECT has been added. See docs of cds::threading namespace for details
    3. Fixed errors in the "Pass-the-Buck" garbage collector (namespace cds::gc::ptb)
    4. [Bug 3128148] The code is aligned with the C++ standard (minor violations has been removed)
    5. [Bug 3141654] missing break statement for atomic store - fixed
    6. Added in-place scan strategy to cds::gc::hzp::GarbageCollector that does not allocate any memory.
    7. Fixed bugs in HRC and tagged GC

0.7.0 05.12.2010 (beta)
    1. Preliminary support for "Pass The Buck" memory manager is added. See cds::gc::ptb namespace.
    2. Many part of library is rewritten to generalize the usage of various GCs
    3. The new class cds::details::aligned_allocator has been added for allocating aligned memory
       blocks. It is useful for Tagged Pointer memory reclamation schema (cds::gc::tagged_gc).
    4. [Break change] New argument has been added to the member functions "ensure" and "find"
       for ordered list and map classes
    5. New member function "emplace" has been added to ordered list and map classes. This member function
       allows change the value (or a part of it) of list/map item.
    6. The internal structure of class cds::map::MichaelHashMap is completely refactored to support
       cds::gc::no_gc correctly
    7. The classes RecursiveSpinT, RecursiveSpin32, RecursiveSpin64, and RecursiveSpin from cds::lock
       namespace have been renamed to ReentrantSpinT, ReentrantSpin32, ReentrantSpin64, and ReentrantSpin
       respectively
    8. Compiler support: GCC version below 4.3.0 is not supported
    9. Fixed memory leak in cds::map::SplitOrderedList
   10. Added compiler barrier to spin-lock release primitive for x86 and amd64
   11. Makefile script is changed to resolve the problem when an user calls 'make clean' directly.
       Thanks to Tamas Lengyel to point me to this bug.
   12. The file dictionary.txt is excluded from distributive. This file is used for testing purposes only.
       You may create dictionary.txt in this way:
        cd ./tests/data
        perl -X split.pl

0.6.0 26.03.2010 (beta)
    1. The library is rewritten using atomic primitives with explicit memory ordering (based on C++
       memory model proposal). The implementation of atomic primitives for supported architectures
       is developed from scratch.
    2. Total refactoring

0.5.0 31.12.2009  (beta)
    First release