cds / News: Recent posts

Version 2.1.0 is available

  • 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++
Posted by khizmax 2016-01-06

Version 2.0.0 is available

  • 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
  • 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
Posted by khizmax 2014-12-30

Version 1.6.0 is available

  • 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
Posted by khizmax 2014-09-23

Version 1.5.0 is available

  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. 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/sample/ 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.
Posted by khizmax 2013-12-29

Version 1.4.0 is available

  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 С++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
Posted by khizmax 2013-05-19

Version 1.3.1 is available

This is bugfix release:
- Fixed building libcds with boost versions before 1.48. Thanks Lucas Larsch who points me to this problem.

Posted by khizmax 2013-01-27

Version 1.3.0 is available

  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.... read more

Posted by khizmax 2012-12-29

Version 1.2.0 is available

1. Add: MichaelDeque - deque lock-free algo discovered by Maged Michael

2. Add: BasketQueue - Michael's queue modification discovered by Nir Shavit et al.

3. Add: support of Clang 3.0, 3.1 compiler for amd64, x86 (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

Posted by khizmax 2012-08-20

Version 1.1.0 is available

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

Posted by khizmax 2012-04-17

Version 1.0.0 is available

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

Posted by khizmax 2011-12-31

Version 0.8.0 is available

This is general release. New features:
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 (
5. Added: support for FreeBSD amd64, x86

Posted by khizmax 2011-03-28

Version 0.7.2 is available

This is bug-fix release.

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.... read more

Posted by khizmax 2011-02-27

Version 0.7.1 is available

This is bug-fix release

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. The strategy does not allocate any memory.
7. Fixed bugs in HRC and tagged GC

Posted by khizmax 2010-12-29

Version 0.7.0 is available

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
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 exluded from distributive. This file is used for testing purposes only.

Posted by khizmax 2010-12-05

Version 0.6.0 is available

The CDS library is totally rewritten using atomic primitives with explicit memory ordering (based on C++ memory model proposal). The implementation of atomic primitives for supported processor architectures is developed from scratch.

Posted by khizmax 2010-03-26

Version 0.5.0 (first beta)

This library is an attempt to implement the well-known lock-free algorithms and memory reclamation schemas: Michael & Scott's queue, Michael's hash map, split-ordered list by Shalev & Shavit, Hazard Pointer memory reclamation by Michael's and its modification created by Sundell & Gidenstam and much more.
Supported platforms are:
GNU GCC 4.3:
x86 Linux (32bit)
amd64 (x86-64) Linux (64bit)
ia64 (itanium) Linux (64bit)
ia64 (itanium) HP-UX 11.23 and HP-UX 11.31 (64bit)
sparc (ultrasparc-III) Sun Solaris (64bit)
Microsoft Visual C++ 2008:
x86 Windows (32bit)
amd64 (x86-64) Windows (64bit)

Posted by khizmax 2010-01-10

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