Simgrid

The Easter Christmas Release (this one is somewhat late).

Python:
- We are excited to introduce the SimGrid/S4U interface to your neighborhood
- Not complete yet: asynchronous activities (amongst others) are still missing
- Still ongoing: the interface may change in the future. We need more
testers! Please report any glitches.
- No new project using Java should start now. Please switch to Python.

General:
- Some of the internal cleanups may lead to speed improvements:
- The hard limitation on the amount of simulated actors with
Java+Mac was removed. Now, the available memory is the only limit.
- Our refcounting was tidyied, leading to 10% speedups in some cases.
- We are still working on making our code robust to the actor kills
and hosts' churn. Things are improving, but it's not perfect yet.
- Replaced our own code to display a backtrace (that was forking addr2line)
with the Boost.Stacktrace library.
You won't see your backtraces without this optional dependency.
- Bump cmake dependency to 3.5 (provided by Ubuntu 16.04).
- Stop setting random seed with srand() at initialization.

XML
- In <host> and <peer>, 'availability_file' is now 'speed_file'.
XML file version remains 4.2 since old files are still compatible.

Java:
- Process termination which was broken at version 3.21 has been repaired.
- Expose host load plugin: loadInit, getCurrentLoad, getComputedFlops, getAvgLoad
- Hide the examples into examples/deprecated. New users should use Python.

MSG:
- Drop MSG_process_create_from_stdfunc() from the API.
This C++ function was a pimple in the C API, made necessary at some
point by the Java bindings. This is fixed now.
- Hide the examples into examples/deprecated. New users should use S4U.
- MSG_process_create and MSG_process_attach now crash if the host used
to run this process is off.
- Fix the protype of MSG_process_on_exit()
Now use (int,void*) callbacks instead of (void*,void*) ones.
The implementation was ways too messy to actually work, I guess.

SMPI:
- Change the way SMPI_SAMPLE_* macros work to avoid invalidating cache
too often and provide more accurate timings.
- Add -gdb, -lldb, and -vgdb shortcuts to help debug MPI codes with smpirun
- MPI_Alltoallw support
- Partial MPI nonblocking collectives implementation: MPI_Ibcast, MPI_Ibarrier,
MPI_Iallgather, MPI_Iallgatherv, MPI_Ialltoall, MPI_Ialltoallv, MPI_Igather,
MPI_Igatherv, MPI_Iscatter, MPI_Iscatterv, MPI_Ialltoallw.
- MPI_Request_get_status, MPI_Status_set_cancelled, MPI_Status_set_elements
support
- Basic implementation of generalized requests (SMPI doesn't
allow MPI_THREAD_MULTIPLE) : MPI_Grequest_complete, MPI_Grequest_start

XBT:
- Drop sg_cmdline. Please use xbt_cmdline instead.
- Drop the C xbt_os_mutex_t; Use the C++11 std::mutex.
- Drop the C xbt_os_sem_t; Use the C++ xbt::OsSemaphore.
OsSemaphore is implemented in a portable way with C++11 threads.
This should allow much more threads to be created at the same time,
allowing Mac and Java users to simulate many more actors.
- Implement the 'thread' factory with std::thread instead of xbt ones.
It is not possible to set the stack size with threads anymore, but
-fsplit-stack is the way to go nowadays when using threads.
- Drop the xbt_os_thread_t module (now unused)
- Drop xbt_ex_display(), use simgrid::xbt::log_exception() instead.
- Drop xbt_str_join_array().
- Drop cunit, use Catch2 instead.

Kernel:
- Many cleanups in the kernel::activity namespace. This was long
overdue, and shall open the path to many future endeavors.

Fixed bugs:
- 132: Java: a process can not shut down its own host
- 220: S4U: detached send causes exception if sender terminates soon after sending
- 261: Document the parameters of parallel execution's constructor
- 300: [s4u] BarrierPtr is missing
- 314: SMPI args internal cleanup
- 316: Fix a bug related to the CPU utilization of multi-core VM
- 318: Invalid trace file when using option --cfg=tracing/smpi/display-sizes:yes
- 324: S4U: Attempting to create an actor on turned off host segfaults instead of throwing
- 325: Turning off a host has different behavior on sleeping actors and computing actors

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The Restarting Documentation (TRD) Release.

Documentation:
- Convert the user manual to Sphinx for improved usability.
Unstable version now hosted on https://simgrid.frama.io/simgrid
Many glitches remain; stay tuned.
- Restrict the Doxygen reference API to the installed header files.
(documenting all internals this way is overkill + doxygen scales badly)
- New tutorial on S4U (highly inspired from the old MSG one, but with
a git repository to fork as a starting point, and a docker image)
- Started but not finished an SMPI tutorial inspired from the JLPC'14 one.
- The Developper manual is still to be converted (not compiled until then)
- Some parts are still missing in this conversion (such as the
platform and deployment sections) while others were blindly converted
and would need more love (such as the configuration flags).
Things will certainly further improve in the future releases.

S4U new features:
- Fully reimplement auto_restart mechanism that was utterly broken
(fix 22, 131 and 281 that were all very related)
- Implement semaphores (fix 303 and 291)
- When creating an actor from a function and its parameters,
move-only parameters are not allowed anymore, as it would prevent
the actor to be restartable if its parameters are consumed on run.
- s4u::Io: IOs go asynchronous as activities. New methods in s4u::Storage:
- io_init(sg_size_t, s4u::Io::OpType) to create a READ or WRITE asynchronous
IO operations that can be started, waited for, or canceled as a regular
activity.
- read_async(sg_size_t) and write_async(sg_size_t) which are wrappers on
io_init() + start()

Tracing:
- Rename 'power' and 'power_used' variables into 'speed' and 'speed_used'
- New host variable: 'core_count'

XBT:
- Remove xbt_os_thread_specific features
- Remove portability wrapper to condition variables
- Remove xbt_os_thread_yield()

SMPI:
- MPICH collective selector now mimics MPICH 3.3b
- OpenMPI collective selector now mimics OpenMPI 3.1.2 (default "tuned" setting)
- MPI_Init(NULL,NULL) is now allowed
- smpi/wtime option now injects time in gettimeofday or clock_gettime calls
- Command-line arguments should now be handled properly in Fortran simulations
- MPI Attributes and related callbacks should work in Fortran
- Apps using C + Fortran should now work
- MPI_* calls now check for non MPI_SUCCESS return values and emit warnings
- Support MPI_Error_String

Java:
- Due to an internal bug, Msg.run() must now be your last line.
We hope to fix it in a future release, and we are sorry for the inconvenience.

Fixed bugs:
- 22: Process autorestart seem to only work with CAS01 cpus
- 56: Feature request: dynamic SMPI replay
- 93: simgrid should not eat --help
- 111: How to change the loopback link characteristics?
- 116: Platform cluster radical
- 117: Platform cluster/host order
- 129: Replay_multiple on steroid
- 131: Java : autostart does not work
- 143: Setting a breakpoint at a given time
- 235: Network energy models should be integrated
- 264: Add ptask L07 resource tracing
- 271: Dynamic and manual replay of SMPI traces
- 279: Breakpoints option uses time deltas instead of absolute time
- 281: Daemonized actor no longer daemonized after an auto-restart
- 282: TIT convertor erase traces when using absolute path in the trace list file
- 285: segfault when a s4u actor kills itself with msg process tracing activated
- 286: Pajé traces are not exposing the number of cores
- 287: Command-line parsing should stop when encountering '--'
- 288: MPI_Init(NULL, NULL)
- 289: Improve documentation of Actor::on_destruction and this_actor::on_exit()
- 290: Method to check if a mailbox has a message ready to be consumed
- 291: [s4u] semaphores do not seem available yet
- 294: Alltoall collective implementation of mpich
- 295: Starting a Host as OFF is not supported
- 296: DTD too permissive
- 299: Add a s4u barrier example

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The proxy snake_case() release.

S4U:
- The whole API is now using snake_case() instead of mixing it with camelCase.
Compatibility wrappers in place for one year.
- We took the opportunity to increase the consistency of the API.
Please report any remaining glitches.
- New function simgrid::s4u::Host::get_actor_count:
Returns the number of actors running on a specific host.

SMPI:
- SMPI is now tested with ~45 proxy apps from various sources, with none or
only minor patching needed: check https://github.com/simgrid/SMPI-proxy-apps
- Replay: The replay file has been re-written in C++.
- Replay: Tags used for messages sent via MPI_Send / MPI_Recv are now
supported. They are stored in the trace and used when replayed.
- Basic support of MPI_Cancel. Robustness not guaranteed.
- Support of MPI_Win_allocate_shared, MPI_Win_shared_query, MPI_Comm_split_type
(only for MPI_COMM_TYPE_SHARED).
- New option: smpi/privatize-libs, to add external shared libs to be privatized
by SMPI. They will be copied locally and loaded separately by each process.
Example --cfg=smpi/privatize-libs:"libgfortran.so.3;libscalapack.so".
- Tracing: add tracing for MPI_Start, Startall, Testall, Testany
- Interception of getopt, getopt_long and getopt_long_only calls to avoid issues
with internal index optind with multiple processes. Only works if MPI_Init has
already been called.
- Fortran: SMPI builds a mpi.mod file which should allow use of "use mpi"
syntax without preprocessing tricks.

TRACE
- Change --cfg=tracing/msg/vm to --cfg=tracing/vm as virtual machine
behavior tracing is no longer limited to MSG
- TIT (Time Independent Traces): We finally support tags. Unfortunately,
this means that traces now need to be updated or re-obtained; both Irecv
and Isend lines in your traces have now in total 5 mandatory fields:
<rankid> <command> <to/from rankid> <tag> <size>
To update your traces, it suffices to add a 0 for the tag here.
- TIT now also supports waiting for a distinct request via MPI_Wait.
Wait/Test now wait for a specific request, not just the last one that was
issued. This unfortunately means another update, because we need to
identify which request you want to wait for. We do this via the
triplet (sender, receiver, tag), which needs to be added:
<rankid> <command> <sender> <receiver> <tag>
- Actions are now in lower case (e.g., "allReduce" becomes "allreduce").
New script simgrid_convert_TI_traces.py: upgrade your TI traces.

MSG
- The deprecation of MSG is ongoing (but this should not impact you).
Many MSG functions are now simple wrappers on the C API of S4U. If
you wish to convert your code to S4U, find the S4U counterparts of
your MSG calls in src/msg/msg_legacy.cpp.
- MSG can still be used, but won't evolve anymore.

Plugins:
- Allow to run the Link energy plugin from the command line with
--cfg=plugin:link_energy
- Rename Energy plugin into host_energy
- Rename Load plugin into host_load

Simix:
- Add parameter --cfg=simix/breakpoint to raise a SIGTRAP at given time.
- kill simix::onDeadlock() that was somewhat dupplicating s4u::on_deadlock()
- Improve performance when handling timeouts of simix synchros.

XBT:
- Config: the C API is now deprecated (will be removed in 3.23), and
the C++ API has been slightly improved.

Other:
- Fix several build issues on OSX.
- Move simgrid_config.h to simgrid/config.h (old header still working)

Fixed bugs:
- 143: Setting a breakpoint at a given time
- 150: Inconsistent event names in SMPI replay
- 258: daemonized actors hang after all non-daemonized actors have completed
- 267: Linker error on unit_tmgr
- 269: SMPI: tracing of MPI_Wait/all/any broken
- SMPI: Fix various crashes with combined use of MPI_PROC_NULL and MPI_IGNORE_STATUS

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The Fixed ABI Release.

As you may know, we are currently refactoring SimGrid in deep.
Upcoming SimGrid4 will be really different from SimGrid3: modular,
standard and extensible vs. layered, homegrown and rigid. C++ vs. C.

Our goal is to smooth this transition, with backward compatibility
and automatic update paths, while still progressing toward SimGrid4.

SimGrid remains open during works: The last pure SimGrid3 release was
v3.12 while all subsequent versions are usable alpha versions of
SimGrid4: Existing interfaces remain unchanged, but the new S4U
interface is budding and the internals are deeply reorganized.

Since 2015, we work hard to reduce the changes to public APIs. When
we need to rename a public library symbol in S4U, we let your
compiler issue an explicative warning when you use the deprecated
function. These messages remain for four releases, i.e. for one full
year, before turning into an error. Starting with v3.15, your can
also adapt to API changes with the SIMGRID_VERSION macro, that is
defined to 31500 for v3.15, to 31901 for v3.19.1 and so on.

Starting with this v3.19.1, our commitment to reduce the changes to
the public interfaces is extended from the API to the ABI: a program
using only MSG or SimDag and compiled against a given version of
simgrid can probably be used with a later version of SimGrid without
recompilation. We will do our best... but don't expect too much of
it, that's a really difficult goal during such profund refactoring.

The difference between v3.19 and v3.19.1 is that the former was
accidentally breaking the ABI of MSG, while the later is restoring
the previous ABI.

S4U and kernel APIs will still evolve until SimGrid4, with one-year
deprecation warnings as currently. In fact, cleaning up these
interfaces and converting them to snake_case() is one release goal of
v3.20. But don't worry, we are working to smooth this upgrade path.

In summary, new projects should start with S4U to benefit of the
future, but old MSG projects should still be usable with no change.

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The Moscovitly-cold Spring release.

SMPI user-visible improvements:
- Support of MPI_Type_create_subarray
- Unimplemented MPI calls now abort (instead of issuing a warning)
Some harmless calls around errhandlers still only issue a warning.
- MPI_Sendrecv was behaving badly when MPI_PROC_NULL was sender or receiver.
- Starting MPI ranks (or even MSG/S4U actors) once the simulation started
is now possible (mmap privatization was refactored to this end).
Adding new SMPI instances should also be technically doable now.

SMPI internal cleanups:
- Removed index notion from SMPI -- no more "getPid() - 1"!
In tracing files, actors are called rank-<PROCESS-ID> but these are
NOT the real ranks (tracing several communicators is not supported yet).
- Deprecate smpi_process_index() (will be removed in 3.22)
- Better testing on classical proxy apps, through an external project:
https://github.com/simgrid/SMPI-proxy-apps/

Documentation
- Use a graphical TOC to make it easier to find the documentation you need
- Revamp the MSG tutorial

MSG
- Fix MSG_task_get_remaining_work_ratio(): return 1.0 for unstarted tasks.
- Remove parameter of MSG_process_killall().
Resetting the PID was bogus anyway (several actors could have the same PID).

S4U
- Execution->setHost() can be called after start(), to migrate it.
- Comm::test_any() is now implemented.
- s4u::Actor now has onCreation() and onDestruction() signals.
- Install some kernel header files for the users' plugins and more.
Warning, their API is really not stable yet.
include/simgrid/kernel/resource/{Action,Resource,Model}.hpp
include/simgrid/kernel/routing/*Zone.hpp

SimDag
- SD_task_dependency_add(): remove unused parameters 'name' and 'data'.

Build System and other cleanups:
- Remove unused run-time parameter "tracing/onelink-only".
- SimGrid now works with intel compilers (MC still buggy)
- Remove XBT_LOG_CONNECT, it should be useless nowadays.
- tesh kills subprocesses on timeout (but not on windows)

PLATFORM:
- Rename FULLDUPLEX into SPLITDUPLEX (old name still accepted)

Fixed bugs:
- 194: Feature request: simgrid::s4u::Comm::test_any()
- 245: migrating an actor does not migrate its execution
- 253: Feature Request: expose clusters as objects
- 254: Something seems wrong with s4u::Actor::kill(aid_t)
- 255: Tesh broken on Windows
- 256: Modernize FindSimGrid.cmake
- 257: Fix (ab)use of CMake install

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The "Ho Ho Ho! SimGrid 4 beta is coming to town" release.

MSG IS NOW DEPRECATED. Please use S4U for new projects.
- Support for MSG should not be removed from SimGrid before 2020,
but future evolutions will be limited to the integration of
user-provided patches.

S4U New features
- s4u::onDeadlock() signal, run before stopping the simulation.
- s4u::Exec: asynchronous executions (abstraction of background
threads)
- s4u::Host->getLoad() returns the achieved speed in flops/s

S4U API changes
- Link::name() is deprecated and will be removed in v3.21, use
Link::getCname() instead.
- Mailbox::getName() changed to return a std::string, use
Mailbox::getCname() instead to get a char*.
- Storage::getName() changed to return a std::string, use
Storage::getCname() instead to get a char*.
- s4u::allStorages() becomes s4u::getStorageList(whereTo)
to have both allocation and deallocation of the map in user space.

MSG
- Forbid the use of MSG_task_get_flops_amount() on parallel tasks:
The amount of flops remaining to do is a vector, not a scalar.
- Introduce MSG_task_get_remaining_work_ratio(), which does what its
name implies on both sequential and parallel tasks.
- Both changes fix GitHub's 223 using PR 237 as a basis.
Thanks Michael Mercier.
- Most examples were converted to S4U and hidden elsewhere at tests.
Rationale: we still want MSG to work; we want newcomers to use S4U.

SURF
- LMM stuff moved to its own namespace: simgrid::kernel::lmm.
- Renamed LMM classes (e.g. s_lmm_system_t -> System).

SMPI
- Switch to the faster dlopen privatization mechanism by default
- Documentation improvments

Virtual Machines
- Live migration is getting moved to a plugin. Dirty page tracking is
the first part of this plugin. This imply that VM migration is now
only possible if one this function is called:
- C/MSG: MSG_vm_live_migration_plugin_init()
- C/C++: sg_vm_live_migration_plugin_init()
- Java: Msg.liveMigrationInit()
For C and C++, "simgrid/plugins/live_migration.h" also has to be
included.

XBT
- Define class simgrid::xbt::Path to manage file names.
- Removed unused functions:
- xbt/file.h: xbt_basename(), xbt_dirname(), xbt_getline()
- xbt/graph.h: xbt_graph_edge_get_length(), xbt_graph_edge_set_length,
xbt_graph_export_graphviz()
- xbt/str.h: xbt_str_join()
- Remove unused datatypes:
- xbt/heap.h: use std::priority_queue or boost::heap instead
- xbt/swag.h: use boost::intrusive::list instead

PLUGINS:
- New link_energy plugin for the consumption of the links.
- All of the operations on files and storage contents have been
packaged into a plugin (src/plugins/file_system). The current
public interface can be found in
include/simgrid/plugins/file_system.h
To use these functions you now have to initialize the plugin by
calling MSG_storage_file_system_init() just after calling
MSG_init() or sg_storage_file_system_init() just after creating
the Engine.

XML
- Remove the undocumented/untested tag <include>

TRACE
- Remove viva specific tracing as the tool is no longer maintained

Fixed bugs:
- 248: Kill of finished processes leads to segfault
- 240: xbt_cond_wait_timeout should gracefully return for C apps
- 239: please implement signal s4u::onDeadlock()
- 230: segfaults when exit() without run()
- 225: s4u::Actor::kill() doesn not really kill victims in a join()
- 223: MSG_task_get_flops_amount() not working with parallel tasks
- 222: Actor::kill() doesn't really kill and segfaults
- 221: odd LMM warning when killing an actor
- 120: Memory leak when the processes are forcefully killed

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