[lttng-dev] [RELEASE] Userspace RCU 0.9.0

Mathieu Desnoyers mathieu.desnoyers at efficios.com
Fri Oct 16 15:58:20 EDT 2015


liburcu is a LGPLv2.1 userspace RCU (read-copy-update) library. This
data synchronization library provides read-side access which scales
linearly with the number of cores. It does so by allowing multiple
copies of a given data structure to live at the same time, and by
monitoring the data structure accesses to detect grace periods after
which memory reclamation is possible.

liburcu-cds provides efficient data structures based on RCU and
lock-free algorithms. Those structures include hash tables, queues,
stacks, and doubly-linked lists.

New and Noteworthy

Two years after the 0.8.0 release, it's about time we release
Userspace RCU 0.9.0 with some interesting new features:

* liburcu.so and liburcu-bp.so now use the membarrier system call
  to speed up RCU read-side critical sections when available. It
  is newly introduced in Linux 4.3. See kernel/membarrier.c in a
  recent Linux kernel tree for details.
* Port Userspace RCU to Android,
* Port Userspace RCU to Solaris 10 and 11,
* Refactoring of tests into the following make targets:
  # Short sanity check
  make check
  # Few minutes regression testing
  make regtest
  # Few tens of minutes benchmarks
  make short_bench
  # Hours-long benchmarks
  make long_bench
* Tests now output in "tap", for easier integration in continuous
  integration. See https://ci.lttng.org/job/liburcu/ for the
  Userspace RCU CI job.
- Port to aarch64 and powerpc64le architectures,
- Port to hppa/PA-RISC architecture,

Note: the soname major has been bumped to 4 even though it really
only needed to be bumped to 3.

2015-10-16 Userspace RCU 0.9.0
        * Bump soname major to 4
        * Cleanup: remove trailing tab
        * Fix: Use proper macro to detect stdbool.h
        * Configure: Add missing checks
        * Port: Add Solaris build instructions
        * Fix: regtest outputs valid TAP protocol
        * Port: Detect nproc bin name in benchmark scripts
        * Port: Add Solaris getcpu support
        * Port: Fixes to build system for portability
        * Port: Add Solaris support to tests/common/thread-id.h
        * Port: Add Solaris support to urcu/syscall-compat.h
        * Port: replace bzero() by memset()
        * Port: make bootstrap script work on most shell
        * tests: rcutorture: use parameters rather than random
        * Fix: only define membarrier system call on Linux
        * Refactor tests
        * Fix: cast caa_cycles_t to unsigned long long
        * caa_get_cycles: caa_ prefix for type, use CLOCK_MONOTONIC
        * Cleanup: remove trailing whitespaces at EOL
        * Cleanup: move generic caa_get_cycles to arch/generic.h
        * tile: allocate membarrier system call number
        * ia64: allocate membarrier system call number
        * aarch64: allocate membarrier system call number
        * powerpc64le: use "ppc" architecture
        * arm: allocate membarrier system call number
        * s390: allocate membarrier system call number
        * ppc: allocate membarrier system call number
        * lfstack: relax constraints on node re-use
        * Fix: format string signedness
        * Cleanup: tests: Branch condition evaluates to a garbage value
        * Fix: test: unchecked return value
        * Fix: test: side-effect in assertion
        * x86: allocate membarrier system call number
        * urcu-bp: use sys_membarrier when available
        * Cleanup: urcu: remove unused membarrier "group" parameter
        * urcu/ref.h: implement urcu_ref_get_unless_zero()
        * Fix: compat_futex: uninitialized ret variable
        * Fix: compat_futex_noasync: don't override return value
        * Fix: dynamic fallback to compat futex on sys_futex ENOSYS
        * Detect RCU read-side overflows
        * Detect RCU read-side underflows
        * Introduce urcu_assert and registration check
        * Fix: volatile in assert()
        * Update following changes to sys_membarrier ABI
        * uatomic: Specify complete types for atomic function calls
        * Cleanup: remove unused return value warning from tests
        * Fix: handle sys_futex() FUTEX_WAIT interrupted by signal
        * Fix: compat_futex.c: *uaddr should be read as volatile
        * Cleanup: cast poll delay return value to void
        * tests: Convert unit tests to TAP
        * Fix: make benchmark test run in oot build
        * Fix: call_rcu_thread() affinity failure
        * Cleanup: cast poll delay return value to void
        * Cleanup: cast poll delay return value to void
        * Cleanup: cast poll delay return value to void
        * Cleanup: cast poll delay return value to void
        * Cleanup: cast poll() return value to void for delays
        * urcu: fix deprecation warning with new glibc
        * urcu: add cds_list_for_each_entry_safe_from macro
        * Fix: deadlock when thread join is issued in read-side C.S.
        * Fix: rename RCU_DEBUG to DEBUG_RCU in urcu-qsbr.h
        * Cleanup some c99 pedantic warnings
        * Mark braced-groups within expressions with __extension__
        * Fix: compat_futex_noasync race condition
        * tests: Use stderr redirection for time output
        * Fix: use space after rpath for OS X ld
        * Fix: move transparent union attribute after union declaration for clang
        * Configure: add check for used type
        * Configure: add missing check of headers
        * Configure: add missing check for funcs: memset, strerror
        * Fix: documentation: urcu-pointer.h: s/rcu_dereference_pointer/rcu_dereference/
        * urcu-bp/urcu-qsbr: remove unneeded DEBUG_YIELD code
        * Fix: call rcu should call internal RCU API
        * Fix: silence gcc -Wextra warning
        * compiler: use __GNUC__ instead of the undefined __GNUC_MAJOR__
        * Fix: lfstack reversed empty/non-empty return value
        * lfstack: fix: add missing __cds_lfs_init
        * wfstack: add missing union parameters
        * Fix: preserve example files' timestamps when copying
        * wfstack: implement mutex-free wfstack with transparent union
        * wfcqueue: Implement mutex-free wfcqueue head with transparent union
        * lfstack: Implement mutex-free stack head with transparent union (v2)
        * rculfhash: remove duplicated code
        * rculfhash: handle pthread_create failures
        * rculfhash: fall back to single-threaded resize on calloc failure
        * x86: drop extra semi-colon in caa_cpu_relax
        * Cleanup: tests: cast console write return value as void
        * Modernize doc using Markdown
        * Fix: update automake following README to README.md change
        * Modernize README using Markdown
        * Fix: incorrect parenthesis in cds_hlist_for_each_entry_safe_2
        * Fix: Use after free in rcu_barrier()
        * Fix: rcu_barrier(): uninitialized futex field
        * call_rcu threads should clear their PAUSED flag when they unpause
        * test_urcu_fork: test many fork, with 3 children deep
        * Update list of supported architectures in README
        * Add support for hppa/PA-RISC architecture
        * Use autoconf AM_MAINTAINER_MODE
        * Use gcc atomics on aarch64/powerpc64le
        * Fix: move wait loop increment before first conditional block
        * Fix: high cpu usage in synchronize_rcu with long RCU read-side C.S.
        * Fix: out of tree build: doc/examples
        * Fix: out of tree build tests/common
        * tests/unit: use lib rather than source
        * automake: Rename INCLUDES to AM_CPPFLAGS (new name)
        * tests regressions: use lib rather than recompile from source
        * tests: use common lib rather than recompile compat sources
        * urcu tests: use lib rather than compile from source
        * urcu mb tests: use lib rather than recompile from source
        * urcu signal tests: use library rather than recompile source
        * tests: move yield debug to common test library
        * tests urcu bp: use lib rather than recompile source
        * test_urcu_defer: link on urcu lib rather than recompile source
        * tests/benchmark: use urcu qsbr lib rather than recompile from source
        * Pass the CC variable to the example Makefiles
        * Fix: urcu-bp interaction with threads vs constructors/destructors
        * x86 barrier for Xeon Phi: use rsp on x86-64
        * Set RCU_HAVE_FENCE to false on Intel Xeon Phi
        * Fix undefined NULL pointer arithmetic in hlist
        * Cleanup: Check for pthread in Libc
        * Cleanup: Android: Do not redefine gettid
        * Fix undefined NULL pointer arithmetic
        * Android: implement rand_r()
        * Android: do not redefine gettid on Android
        * Android: add a compat layer for 'syscall.h'
        * Android: do not link pthread on Android
        * Android: configure.ac Android check
        * Blacklist ARM gcc 4.8.0, 4.8.1, 4.8.2
        * rculfhash: document max_nr_buckets = 0
        * Library major version number (soname) increment to 3
        * Fix: tls-compat multi-lib conflict
        * Use cross compiler for doc examples
        * Add lttng-dev mailing list to readme
        * wfcqueue: remove misleading comment
        * gcc warning fixes: -Wsign-compare and -Wextra
        * Fix: urcu-qsbr: reversed logic on RCU_DEBUG
        * Fix: urcu-bp segfault in glibc pthread_kill()
        * Fix urcu-bp: don't move registry
        * Fix: compat futex duplicated lock and completion
        * Fix: i386 compat code duplicated mutex instances
        * Fix: urcu-bp: Bulletproof RCU arena resize bug
        * Fix: test_mutex.c uninitialized mutex

Project website: http://liburcu.org
Git repository: git://git.liburcu.org/urcu.git

Mathieu Desnoyers
EfficiOS Inc.

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