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ChangeLog

This is the ChangeLog for public releases of UPC++.

For information on using UPC++, see: README.md
For information on installing UPC++, see: INSTALL.md

2019.09.14: Release 2019.9.0

New features/enhancements: (see specification and programmer's guide for full details)

  • upcxx has several new convenience options (see upcxx -help)
  • upcxx::rput(..., remote_cx::as_rpc(...)) has received an improved implementation for remote peers where the dependent rpc is injected immediately following the put. This pipelining reduces latency and sensitivity to initiator attentiveness, improving performance in most cases (for the exception, see issue #261).
  • Accounting measures have been added to track the shared-heap utilization of the UPC++ runtime (specifically rendezvous buffers) so that in the case of shared-heap exhaustion an informative assertion will fire. Also, fewer rendezvous buffers are now required by the runtime, thus alleviating some pressure on the shared heap.
  • Environment variable UPCXX_OVERSUBSCRIBED has been added to control whether the runtime should yield to OS (sched_yield()) within calls to upcxx::progress()). See docs/oversubscription.md.
  • Release tarball downloads now embed a copy of GASNet-EX that is used by default during install. Git clones of the repo will still default to downloading GASNet-EX during install. The GASNET envvar can still be set at install time to change the default behavior.
  • A CMake module for UPC++ is now installed. See 'Using UPC++ with CMake' in README.md
  • atomic_domain<float> and atomic_domain<double> are now implemented
  • Interoperability support for Berkeley UPC's -pthreads mode, see docs/upc-hybrid.md
  • New define UPCXX_SPEC_VERSION documents the implemented revision of the UPC++ specification

Support has been added for the following compilers/platforms (for details, see 'System Requirements' in INSTALL.md):

  • PGI v19.1+ on Linux/x86_64
  • PGI v18.10+ on Linux/ppc64le
  • clang v5.0+ on Linux/ppc64le
  • PrgEnv/cray with CCE v9.0+ on the Cray XC
  • ALCF's PrgEnv/llvm v4.0+ on the Cray XC
  • NEW platform: Linux/aarch64 (aka "arm64" or "armv8")
    • gcc v6.4.0+
    • clang 4.0.0+

Notable bug fixes:

  • issue #140: upcxx::discharge() does not discharge remote_cx::as_rpc()
  • issue #168: upcxx::progress_required always returns 0
  • issue #170: team_id::when_here() is unimplemented
  • issue #181: Library linkage failures when user compiles with a different -std=c++ level
  • issue #184: bench/put_flood crashes on opt/Linux
  • issue #203: strict aliasing violations in device_allocator
  • issue #204: No support for nvcc --compiler-bindir=...
  • issue #210: cuda_device::default_alignment() not implemented
  • issue ) does not match spec">#223: operator<<(std::ostream, global_ptr<T>) does not match spec
  • issue .fetch isn't a constant function">#224: missing const qualifier on dist_object<T>.fetch()
  • issue #228: incorrect behavior for upcxx -g -O
  • issue #229: Teach upcxx wrapper to compile C language files
  • issue #234: Generalized operation completion for barrier_async and broadcast
  • issue #243: Honor $UPCXX_PYTHON during install
  • issue #260: GASNET_CONFIGURE_ARGS can break UPC++ build
  • issue #264: upcxx-meta CXX and CC are not full-path expanded
  • issue #268: Completion handlers can't accept && references
  • spec issue #141: resolve empty transfer ambiguities (count=0 RMA)
  • spec issue #142: add persona::active_with_caller()

This library release mostly conforms to the UPC++ v1.0 Specification, Revision 2019.9.0. The following features from that specification are not yet implemented:

  • view buffer lifetime extension for remote_cx::as_rpc (issue #262)
  • User-defined Class Serialization interface (coming soon!)

Breaking changes:

  • Applications are recommended to replace calls to std::getenv with upcxx::getenv_console, to maximize portability to loosely coupled distributed systems.
  • envvar UPCXX_GASNET_CONDUIT has been renamed to UPCXX_NETWORK. For backwards compat, the former is still accepted when the latter is unset.
  • upcxx::allocate() and device_allocator<Device>::allocate() have changed signature. The alignment parameter has moved from being a final defaulted template argument to being a final defaulted function argument.
  • future<T...>::result_moved() and future<T...>::wait_moved() are deprecated, and will be removed in a future release.

2019.05.27: Bug-fix release 2019.3.2

Notable bug fixes:

  • issue #209: Broken install defaulting of CC/CXX on macOS

Fixes the following notable bug in the GASNet library (see https://gasnet-bugs.lbl.gov for details):

  • bug3943: infrequent startup hang with PSHM and over 62 PPN

2019.03.15: Release 2019.3.0

New features/enhancements: (see specification and programmer's guide for full details)

  • Prototype Memory Kinds support for CUDA-based NVIDIA GPUs, see INSTALL.md. Note the CUDA support in this UPC++ release is a proof-of-concept reference implementation which has not been tuned for performance. In particular, the current implementation of upcxx::copy does not utilize hardware offload and is expected to underperform relative to solutions using RDMA, GPUDirect and similar technologies. Performance will improve in an upcoming release.
  • Support for interoperability with Berkeley UPC, see upc-hybrid.md
  • There is now an offline installer package for UPC++, for systems lacking connectivity
  • Barrier synchronization performance has been improved
  • Installer now defaults to more build parallelism, improving efficiency (see UPCXX_MAKE)

Notable bug fixes:

  • issue #100: Fix shared heap setting propagation on loosely-coupled clusters
  • issue #118: Enforce GEX version interlock at compile time
  • issue #177: Completion broken for non-fetching binary AMOs
  • issue #183: bench/{put_flood,nebr_exchange} were failing to compile
  • issue ::dist_object(T , team)">#185: Fix argument order for dist_object constructor to match spec
  • issue #187: Improve Python detection logic for the install script
  • issue #190: Teach upcxx-run to honor UPCXX_PYTHON
  • issue #202: Make global_ptr::operator bool conversion explicit
  • issue #205: incorrect metadata handling in ~persona_scope()

This library release mostly conforms to the UPC++ v1.0 Draft 10 Specification. The following features from that specification are not yet implemented:

  • barrier_async() and broadcast() only support default future-based completion (issue #234)
  • atomic_domain<float> and atomic_domain<double> are not yet implemented (issue and atomic_domain">#235)
  • team_id::when_here() is unimplemented (issue #170)
  • User-defined Class Serialization interface

Breaking changes:

  • envvar UPCXX_SEGMENT_MB has been renamed to UPCXX_SHARED_HEAP_SIZE. For backwards compat, the former is still accepted when the latter is unset.
  • The minimum-supported version of GNU g++ is now 6.4.0
    • This also applies to the stdlibc++ used by Clang or Intel compilers
  • The minimum-supported version of llvm/clang for Linux is now 4.0

2018.09.26: Release 2018.9.0

New features/enhancements: (see specification and programmer's guide for full details)

  • Subset teams and team-aware APIs are added and implemented
  • Non-Blocking Collective operations, with team support: barrier, broadcast, reduce
  • New atomic operations: mul, min, max, bit_{and,or,xor}
  • future::{wait,result}* return types are now "smarter", allowing more concise syntax
  • New upcxx compiler wrapper makes it easier to build UPC++ programs
  • upcxx-run: improved functionality and handling of -shared-heap arguments
  • New supported platforms:
    • GNU g++ compiler on macOS (e.g., as installed by Homebrew or Fink)
    • PrgEnv-intel version 17.0.2 or later on Cray XC x86-64 systems
    • Intel C++ version 17.0.2 or later on x86-64/Linux
    • GNU g++ compiler on ppc64le/Linux
  • rput_{strided,(ir)regular} now provide asynchronous source completion
  • Performance improvements to futures, promises and LPCs
  • UPC++ library now contains ident strings that can be used to query version info from a compiled executable, using the UNIX ident tool.

Notable bug fixes:

  • issue #49: stability and portability issues caused by C++ thread_local
  • issue #141: missing promise move assignment operator

This library release mostly conforms to the UPC++ v1.0 Draft 8 Specification. The following features from that specification are not yet implemented:

  • barrier_async() and broadcast() only support default future-based completion (issue #234)
  • atomic_domain<float> and atomic_domain<double> are not yet implemented (issue and atomic_domain">#235)
  • team_id::when_here() is unimplemented (issue #170)
  • User-defined Serialization interface

Breaking changes:

  • global_ptr<T>(T*) "up-cast" constructor has been replaced with to_global_ptr<T>(T*)
  • atomic_domain now requires a call to new collective destroy() before destructor
  • allreduce has been renamed to reduce_all

2018.05.10: Release 2018.3.2

This is a re-release of version 2018.3.0 (see below) that corrects a packaging error.

2018.03.31: Release 2018.3.0

New features/enhancements:

  • Non-Contiguous One-Sided RMA interface is now fully implemented.
  • Remote Atomics have been revamped, expanded and implemented. See the updated specification for usage details. The current implementation leverages hardware support in shared memory and NIC offload support in Cray Aries.
  • View-Based Serialization - see the specification for details
  • Implementation of local memory translation (achieved with global_ptr::local() / global_ptr(T*)). This encompasses a limited implementation of teams to support upcxx::world and upcxx::local_team so clients may query their local neighborhood of ranks.

Notable bug fixes:

  • issue #119: Build system is now more robust to GASNet-EX download failures.
  • issue #125: Fix upcxx-run exit code handling.
  • Minor improvements to upcxx-run and run-tests.

This library release mostly conforms to the UPC++ v1.0 Draft 6 Specification. The following features from that specification are not yet implemented:

  • Teams: team::split, team_id, collectives over teams, passing team& arguments to rpcs, constructing dist_object over teams.
  • Vector broadcast broadcast(T *buf, size_t count, ...)
  • barrier_async
  • User-defined Serialization interface

This release is not yet performant, and may be unstable or buggy.

Please report any problems in the issue tracker.

2018.01.31: Release 2018.1.0 BETA

This is a BETA preview release of UPC++ v1.0.

New features/enhancements:

  • Generalized completion. This allows the application to be notified about the status of UPC++ operations in a handful of ways. For each event, the user is free to choose among: futures, promises, callbacks, delivery of remote rpc, and in some cases even blocking until the event has occurred.
  • Internal use of lock-free datastructures for lpc queues.
  • Improvements to the upcxx-run command.
  • Improvements to internal assertion checking and diagnostics.

This library release mostly conforms to the UPC++ v1.0 Draft 5 Specification. The following features from that specification are not yet implemented:

  • Teams
  • Vector broadcast broadcast(T *buf, size_t count, ...)
  • barrier_async
  • Serialization
  • Non-contiguous transfers
  • Atomics

This release is not performant, and may be unstable or buggy.

2017.09.30: Release 2017.9.0

The initial public release of UPC++ v1.0.

This library release mostly conforms to the UPC++ v1.0 Draft 4 Specification. The following features from that specification are not yet implemented:

  • Continuation-based and Promise-based completion (use future completion for now)
  • rput_then_rpc
  • Teams
  • Vector broadcast broadcast(T *buf, size_t count, ...)
  • barrier_async
  • Serialization
  • Non-contiguous transfers

This release is not performant, and may be unstable or buggy.

2017.09.01: Release v1.0-pre

This is a prerelease of v1.0. This prerelease supports most of the functionality covered in the UPC++ specification, except personas, promise-based completion, teams, serialization, and non-contiguous transfers. This prerelease is not performant, and may be unstable or buggy. Please notify us of issues by sending email to upcxx@googlegroups.com.

Updated