### Continuous Integration | Drone | Travis | Cirrus | | -------- | ------ | ------- | | [![Build Status](https://cloud.drone.io/api/badges/concurrencykit/ck/status.svg)](https://cloud.drone.io/concurrencykit/ck) | [![Build Status](https://travis-ci.org/concurrencykit/ck.svg)](https://travis-ci.org/concurrencykit/ck) | [![Build Status](https://api.cirrus-ci.com/github/concurrencykit/ck.svg?branch=master)](https://cirrus-ci.com/github/concurrencykit/ck) | Compilers tested in the past include gcc, clang, cygwin, icc, mingw32, mingw64 and suncc across all supported architectures. All new architectures are required to pass the integration test and under-go extensive code review. Continuous integration is currently enabled for the following targets: * `darwin/clang/x86-64` * `freebsd/clang/x86-64` * `linux/gcc/arm64` * `linux/gcc/x86-64` * `linux/clang/x86-64` * `linux/clang/ppc64le` ### Supported Architectures Concurrency Kit supports any architecture using compiler built-ins as a fallback. There is usually a performance degradation associated with this. Concurrency Kit has the following specializations: * `aarch64` * `arm` * `ppc` * `ppc64` * `s390x` * `sparcv9+` * `x86` * `x86_64` ### Features #### Concurrency Primitives ##### ck_pr Concurrency primitives as made available by the underlying architecture, includes support for all atomic operations (natively), transactional memory, pipeline control, read-for-ownership and more. ##### ck_backoff A simple and efficient (minimal noise) backoff function. ##### ck_cc Abstracted compiler builtins when writing efficient concurrent data structures. #### Safe Memory Reclamation ##### ck_epoch A scalable safe memory reclamation mechanism with support idle threads and various optimizations that make it better than or competitive with many state-of-the-art solutions. ##### ck_hp Implements support for hazard pointers, a simple and efficient lock-free safe memory reclamation mechanism. #### Data Structures ##### ck_array A simple concurrently-readable pointer array structure. ##### ck_bitmap An efficient multi-reader and multi-writer concurrent bitmap structure. ##### ck_ring Efficient concurrent bounded FIFO data structures with various performance trade-off. This includes specialization for single-reader, many-reader, single-writer and many-writer. ##### ck_fifo A reference implementation of the first published lock-free FIFO algorithm, with specialization for single-enqueuer-single-dequeuer and many-enqueuer-single-dequeuer and extensions to allow for node re-use. ##### ck_hp_fifo A reference implementation of the above algorithm, implemented with safe memory reclamation using hazard pointers. ##### ck_hp_stack A reference implementation of a Treiber stack with support for hazard pointers. ##### ck_stack A reference implementation of an efficient lock-free stack, with specialized variants for a variety of memory management strategies and bounded concurrency. ##### ck_queue A concurrently readable friendly derivative of the BSD-queue interface. Coupled with a safe memory reclamation mechanism, implement scalable read-side queues with a simple search and replace. ##### ck_hs An extremely efficient single-writer-many-reader hash set, that satisfies lock-freedom with bounded concurrency without any usage of atomic operations and allows for recycling of unused or deleted slots. This data structure is recommended for use as a general hash-set if it is possible to compute values from keys. Learn more at https://engineering.backtrace.io/posts/workload-specialization/ and http://concurrencykit.org/articles/ck_hs.html. ##### ck_ht A specialization of the `ck_hs` algorithm allowing for disjunct key-value pairs. ##### ck_rhs A variant of `ck_hs` that utilizes robin-hood hashing to allow for improved performance with higher load factors and high deletion rates. #### Synchronization Primitives ##### ck_ec An extremely efficient event counter implementation, a better alternative to condition variables. ##### ck_barrier A plethora of execution barriers including: centralized barriers, combining barriers, dissemination barriers, MCS barriers, tournament barriers. ##### ck_brlock A simple big-reader lock implementation, write-biased reader-writer lock with scalable read-side locking. ##### ck_bytelock An implementation of bytelocks, for research purposes, allowing for (in theory), fast read-side acquisition without the use of atomic operations. In reality, memory barriers are required on the fast path. ##### ck_cohort A generic lock cohorting interface, allows you to turn any lock into a NUMA-friendly scalable NUMA lock. There is a significant trade-off in fast path acquisition cost. Specialization is included for all relevant lock implementations in Concurrency Kit. Learn more by reading "Lock Cohorting: A General Technique for Designing NUMA Locks". ##### ck_elide A generic lock elision framework, allows you to turn any lock implementation into an elision-aware implementation. This requires support for restricted transactional memory by the underlying hardware. ##### ck_pflock Phase-fair reader-writer mutex that provides strong fairness guarantees between readers and writers. Learn more by reading "Spin-Based Reader-Writer Synchronization for Multiprocessor Real-Time Systems". ##### ck_rwcohort A generic read-write lock cohorting interface, allows you to turn any read-write lock into a NUMA-friendly scalable NUMA lock. There is a significant trade-off in fast path acquisition cost. Specialization is included for all relevant lock implementations in Concurrency Kit. Learn more by reading "Lock Cohorting: A General Technique for Designing NUMA Locks". ##### ck_rwlock A simple centralized write-biased read-write lock. ##### ck_sequence A sequence counter lock, popularized by the Linux kernel, allows for very fast read and write synchronization for simple data structures where deep copy is permitted. ##### ck_swlock A single-writer specialized read-lock that is copy-safe, useful for data structures that must remain small, be copied and contain in-band mutexes. ##### ck_tflock Task-fair locks are fair read-write locks, derived from "Scalable reader-writer synchronization for shared-memory multiprocessors". ##### ck_spinlock A basic but very fast spinlock implementation. ##### ck_spinlock_anderson Scalable and fast anderson spinlocks. This is here for reference, one of the earliest scalable and fair lock implementations. ##### ck_spinlock_cas A basic spinlock utilizing compare_and_swap. ##### ck_spinlock_dec A basic spinlock, a C adaption of the older optimized Linux kernel spinlock for x86. Primarily here for reference. ##### ck_spinlock_fas A basic spinlock utilizing atomic exchange. ##### ck_spinlock_clh An efficient implementation of the scalable CLH lock, providing many of the same performance properties of MCS with a better fast-path. ##### ck_spinlock_hclh A NUMA-friendly CLH lock. ##### ck_spinlock_mcs An implementation of the seminal scalable and fair MCS lock. ##### ck_spinlock_ticket An implementation of fair centralized locks. ### Compile and Build * Step 1. `./configure` For additional options try `./configure --help` * Step 2. In order to compile regressions (requires POSIX threads) use `make regressions`. In order to compile libck use `make all` or `make`. * Step 3. In order to install use `make install` To uninstall use `make uninstall`. See http://concurrencykit.org/ for more information.