Simgrid

The Ragnar Release (anniversary of the siege of Paris by Vikings in 845)

Main user-visible changes:
- All functions marked as deprecated for one year were removed.
- Removed all that was related to the "Storage" type in all APIs and bindings.
"Disks" have been introduced more than a year ago to replace them for the better.
It's time to finish this replacement.
- SMPI ABI breaks from previous version: MPI global handles (predefined datatypes,
ops, COMM_WORLD) are now defined differently, and can be used in initializers,
avoiding "initializer element is not constant" errors with some codes. Please be
careful to recompile your MPI codes if switching to this new SimGrid version.
- Network model ns-3 now requires version ns-3.28 or higher.
- Removed some option aliases that were deprecated since v3.23 (June 2019)
- 'verbose-exit' is now 'debug/verbose-exit'
- 'simix/breakpoint' is now 'debug/breakpoint'
- 'clean-atexit' is now 'debug/clean-atexit'

S4U:
- New functions: Comm::sendto_{init,async} to initiate a communication
on between two (possibly remote) hosts.
- Define new template functions Mailbox::get_unique(), returning a std::unique_ptr.
- Functions Mailbox::get() and Mailbox::get_async() are now templated with the
type of the pointee. Untyped functions are deprecated. Use Mailbox::get<void>()
or Mailbox::get_async<void>() if you really want to play with void*.
- Unify the interface of Activity::on_{start/activity}
- New function: Comm::get_dst_data()
- New function: Comm::set_payload_size() to set the amount of bytes to simulate.

Models:
- ptask should now work better with multicore hosts (FG37).
- Internal cleanups and refactoring around activities, to prepare for SimDAG++.
- Internal cleanups and refactoring around models, to prepare for programmatic
platform creation.
- Modernize our tests of the performance models

Documentation:
- User manual:
- New section: Configuring the logs from the command line.
- New section: Programming API of logs.
- New section: Getting realistic results
- New section: Examples of SMPI Usage
- New part: SimGrid's Internals, with a section on Design goals
- Move back to the classical Breathe tool chain, and fix many small glitches.

SMPI:
- Handle leak checking: SMPI will now display a message if MPI handles are still
present at the end of a simulation. Option smpi/list-leaks:n will display the n
first leaked pointers and their types.
- smpi/display-allocs option : Display Memory allocations analysis, with hints
about the largest allocations. This only works for allocations with malloc/calloc
and not compiled with SMPI_NO_OVERRIDE_MALLOC
- "-analyze" option in smpirun will activate smpi/display-allocs and smpi/display-timing
- New implemented MPI calls: MPI_File_set_size, MPI_Aint_add, MPI_Aint_diff,
MPI_Type_get_extent_x, MPI_Type_get_true_extent_x, MPI_Status_set_elements_x
- Support for MPI C++ datatypes (MPI_CXX_BOOL, MPI_CXX_FLOAT_COMPLEX,
MPI_CXX_DOUBLE_COMPLEX, MPI_CXX_LONG_DOUBLE_COMPLEX)
- Replay now opens and parses the trace file only once for all ranks when possible.
- Misc fixes:
- better handling of MPI_PROC_NULL
- MPI_Group_incl was broken in some cases
- PAPI tracing now fixed
- MPI_Errhandlers are properly handled for MPI_COMM_WORLD
- SMPI will now fail properly when receive size < sent size, instead of
just setting MPI_ERR_TRUNCATE and keep going.
- Proxy Apps ( https://framagit.org/simgrid/SMPI-proxy-apps ):
- Remove useless build patches and split build/run patches on the page
- Build in parallel when possible
- Test on yum-based systems
- New nightly tested Proxy-apps:
- OpenMPI mpi-test-suite
- Coral MCB, LSMS, Qbox, CLOMP
- ECP/Mantevo Cloverleaf3D, Ember
- Codevault bhtree_mpi

Model checker:
- Only initialize the Dwarf parser when needed, saving 10 seconds in most cases.
- Start to overhaul the implementation to modernize it (still ongoing).

XBT:
- Drop simgrid::xbt::demangle(). Please use boost::core::demangle() instead.
- Drop xbt_dynar_cursor_rm(), xbt_dynar_search_or_negative(),
xbt_str_split_quoted(), xbt_str_split_quoted_in_place().
- Deprecate xbt_dynar_to_array().
- When an exception occurs in kernel mode, display both the actor and kernel stacks.

C binding and interface:
- Rename (lowercase) functions sg_actor_get_PID, sg_actor_get_PPID, sg_actor_by_PID.
- Constness requirement has been lowered for parameter argv of sg_actor_start()
and sg_actor_create() It's now (char* const*). The previous version is still
available as sg_actor_start_() and sg_actor_create_().

Fixed bugs (FG.. -> FramaGit bugs; FG!.. -> FG merge requests)
(FG: issues on Framagit; GH: issues on GitHub)
- FG37: Parallel tasks are limited to 1 core per host
- FG62: Running "smpirun -replay" on large networks
- FG!46: Fix a few potential memory leaks in SMPI colls
- GH343: Wrong consumed energy when an exec timeouts

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The Release release (the French lockdown was eased today).

Important user-visible changes:
- SimGrid now requires a compiler with C++14 support.
Sibling projects should upgrade their FindSimGrid.cmake
- Surf precision default value is now 1e-9, instead of 1e-5. This was changed as
several users had difficulties to understand issues when using high bandwidth or
small latency events. The new value was already the default for SMPI and
should not cause too much performance hit. It can change some simulation
timings if simulation was skipping a lot of small events (which was actually
an issue per see). The old value can be restored with --cfg=surf/precision:1e-5.
- On some network models (L07, CM02, LV08), an implicit loopback link is created
for local communication. Default bandwidth was 500MBps and latency was 15µs,
which was rather bad. Default values have been changed to 10GBps and 0 latency.
Options network/loopback-lat and network/loopback-bw have been added to adapt
these values if needed. Network and routing models already providing separate
loopbacks (clusters and such) are not impacted by this change.
- SMPI now adds 16 bytes of header to each message sent, in order to simulate
metadata that are added to each MPI message by MPI libraries (tag,
src/dest, and communicator information). This may change simulation times
for very small message sizes, but should be more realistic.

New features:
- New routing 'WiFi' that makes it easier to specify a wifi network zone.
- New plugins: wifi_energy and link_load. See the associated examples.
- New examples: wifi networks, and communication suspend.

General:
- LTO is now enabled for Intel/clang compilers.
- LTO behavior on GCC can be parameterized using LTO_EXTRA_FLAG in cmake.
Setting it to "auto" will use all available cores, while setting it to n will
use n cores to speedup link step (usage: cmake -DLTO_EXTRA_FLAG=4).
- Remove obsolete runtime option 'contexts/parallel-threshold'.
- Runtime option 'tracing/msg/process' renamed to 'tracing/actor'. The old name
has been kept for compatibility.
- Finally remove obsolete snake_case() aliases for runtime options.
- Further improve the documentation.

S4U:
- the on_exit() of each actor is also executed when the simulation deadlocks.
- New functions: s4u::Activity:: suspend(), resume() and is_suspended()
An example is provided for s4u::Comm but it should work with Exec and Io.

SMPI:
- Update proxy apps coverage of new ECP apps: 60+ apps now tested nightly on
https://framagit.org/simgrid/SMPI-proxy-apps
- MPI/IO: supports names starting with "./"
- Fortran: many MPI/IO bindings, support for MPI_UB/LB, C MPI_INT/FLOAT/DOUBLE
datatypes.
- smpicc/cxx/ff/f90 now will actually perform definition checks at link time. When
building shared libraries, this may cause issues, so environment variable
SMPI_NO_UNDEFINED_CHECK can be added to disable this.
- most temporary files should now be created in /tmp dir (or equivalent).
If this one does not allow execution of code (noexec flag), this may cause issues.
Please use another tmp directory (using TMPDIR or equivalent system variable)
in this case.

Model-Checker:
- A large refactoring is ongoing, but this should be transparent for users so far.

XBT:
- Drop xbt_str_split().

C binding and interface:
- The return type of the sg_actor_on_exit() callbacks is now 'void'
(int value was previously ignored)
- Many C functions were renamed to follow a common naming style
(sg_object_get_something and sg_object_set_something). As usual, the deprecated
names are kept until version 3.30.
- Many MSG tests were converted to the new S4U's interface in C, that
was extended for that.

Fixed bugs (FG.. -> FramaGit bugs; FG!.. -> FG merge requests)
(FG: issues on Framagit; GF: issues on GForge; GH: issues on GitHub)
- FG41: Add sg_actor_create C interface
- FG43: xbt::random needs some care
- FG48: The Impossible Did Happen (yet again)
- FG50: Suspending an actor executed at the current timestamp fails
- FG52: Zero-seconds timeout : "That's in the past already"
- FG53: Crash while using ns-3 network model
- FG54: How to suspend a comm?
- FG!22: Stochastic Profiles
- FG!24: Documentation and fix for xbt/random
- FG!35: Add a modeling hint for parallel links in doc
- FG!36: [xbt/random] Read/Write the state of the RNG
- FG!42: Link cumulated load plugin
- FG!44: Test condition variable wait_until+notify_all
- GF18137: Allow different stack sizes?
- GH128: Parallelization of simulation with --cfg=contexts/nthreads
- GH139: Allow pthread creation in SMPI
- GH336: Packet-level simulation using SMPI?
- GH345: Error in the LMM while migrating a VM
- GH346: [SMPI] error while loading shared libraries: libsimgrid.so
- GH352: pip install / python setup.py install fail to find pybind11
- GH!337: Fix link_energy plugin for wifi platforms
- GH!339: Add Mailbox set_receiver method to python binding
- GH!344: Cast hugepages macros parameters to int64

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The Palindrom Day Release.

Important user-visible changes:
- Improve the Python usability (stability and documentation).
- A nasty synchronization bug was ironed out, see also below.
- Python's doc was organized as a separate tree, now integrated with C++.
- C bindings of S4U were not part of the doc.
- The C++ doc was also improved as methods are now split by theme.
- Further deprecate MSG: you now have to pass -Denable_msg=ON to cmake.
- This is mandatory to use the Java bindings.
- OFF by default; The plan is to completely remove MSG by 2020Q4 or 2021Q1.
- SimDAG++: Automatic dependencies on S4U activities (experimental)
- Some features are already implemented but not all of them
- Cannot block an activity until it's scheduled on a resource
- No heterogeneous wait_any() that would mix Exec/Comm/Io activities.
- See examples/s4u/{io,exec,comm}-dependent for what's already there.

General:
- Upgrade documented Java dependency to Java 8 (earlier versions don't work).
- Drop support for Viva/Triva (old visualization tools), hence removed
TRACE_get_node_types() and TRACE_get_edge_types() functions.

Python:
- Require pybind11 version 2.4.
- Greatly improve locking during context switches with Python.
- Declaring Python callbacks to this_actor::on_exit is now working.
- No more tests are failing currently, even on win32.

S4U:
- Actor: Merge signals on_migration_start/end into on_host_change
- Actor: Rename migrate() into set_host()
- Disk: Allow users to get the read and write nominal bandwidth values
- Exec: Implement wait_for(timeout)
- Io: Implement wait_for(timeout)

XML:
- Parse errors now raise a simgrid::ParseError that you may want to catch.

Kernel:
- In simgrid::kernel::resource::Model, the methods next_occuring_event*() have
been renamed to fix a spelling error. As usual, the previous definitions are
kept with a deprecation warning. However, to avoid runtime errors, it is now
forbidden to override these deprecated methods in a derived class. Please use
the new names immediately if you need to override them.

XBT:
- Remove unused parameter 'free_ctn' for xbt_dict_set() and xbt_dict_set_ext().
- Drop unused functions for dicts and dynars: xbt_dict_cursor_get_elm,
xbt_dict_get, xbt_dict_get_elm, xbt_dict_get_ext, xbt_dict_get_key,
xbt_dict_remove, xbt_dict_reset, xbt_dynar_compare, xbt_dynar_dump,
xbt_dynar_foreach_ptr, xbt_dynar_free_data, xbt_dynar_free_voidp,
xbt_dynar_init, xbt_dynar_insert_at_as, xbt_dynar_merge,
xbt_dynar_remove_n_at, xbt_dynar_replace, xbt_dynar_search, xbt_dynar_set.
- New module: random, providing classical random numbers generators.

SMPI:
- New option : "smpi/auto-shared-malloc-thresh" which sets a value for
allocations' size above which they are considered "shared" by default (as if
they were performed through SMPI_SHARED_MALLOC macros).
Default = 0 = disabled feature.
Note : malloc, calloc and free are now overridden by smpicc/cxx by default.
This can cause some troubles if codes are already overriding these. If this
is the case, defining SMPI_NO_OVERRIDE_MALLOC in the compilation flags can
help, but will make this feature unusable.
- Input check is now performed much more consistently and outputs precise
warnings for each error found
- New supported calls : MPI_File_set_view, MPI_File_get_view
- MPI I/O now only supports disks, as storage is discontinued.
- MPI I/O allows opening files without specifying absolute path
- Note : SMPI configuration options are now initialized by smpi_init_options()
call, which should be called if SMPI is not being used through smpirun.

Fixed bugs (FG.. -> framagit bugs; FG!.. -> framagit merge requests):
- FG9: Python bindings crashing
- FG39: Missing s4u::Comm::wait_any_for example
- FG42: Add support for ThreadSanitizer (TSan)
- FG!19: Removing RngStream
- FG!20: A module for RNG calls
- FG!21: Choice between ad-hoc and standard distributions implementations
- FG!23: Master
- FG!25: Fix link in Mutex doc
- FG!26: Fix links in SMPI interface doc
- GH31: [MC] please provide an option to make MPI_Send asynchronous
- GH305: Unscheduled tasks are still excuted
- GH313: smpirun: manual outdated w.r.t. --help
- GH321: [S4U] Get task remaining work ratio
- GH323: Crash when an actor turn off his physical host
- GH335: Missing links on dragonfly example svg
- https://lists.gforge.inria.fr/pipermail/simgrid-user/2019-November/004653.html:
MPI_Cart_sub was not working properly. Kudos to Jonathan Borne for the report.

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The Clean Disk Release.

S4U:
- Introduce a s4u::Disk interface to manage the newly introduced <disk>
tag. s4u::Disk is called to supplant s4u::Storage in a near future. It
thus becomes the default resource to execute I/O operations. Examples
and the file system plugin have been modified to use disks instead of
storage elements. Storage can still be used but is doomed to disappear.
Users are thus adviced to update their simulators accordingly.
- Barrier::wait returns SG_BARRIER_SERIAL_THREAD for (only) one actor
for consistency with pthread_barrier_wait()
- Host::get_englobing_zone() returns the englobing netzone
- Actor::on_destruction is now called in the destructor
Actor::on_termination new signal called when the actor terminates
its code.
- Global signals are now part of the Engine:
- on_platform_creation: after config settings, before the XML parsing
- on_platform_created: right after the XML parsing
- on_time_advance: each time the clock advances
- on_simulation_end: after simulation, before cleanups
- on_deadlock: as the name implies.
- C bindings:
- sg_{actor,host,link}_{data,data_set}() now all exist.
Use them to attach user data to the object and retrieve it.

Models:
- Introduce an experimental Wifi model. It sounds reasonable
according to the state of the art, but it still has to be properly
validated, at least against ns-3 if not against reality.
- Improved the usability of ns-3. Several bugs were ironed out.
- host_energy: Wattage was expressed as 'idle:oneCore:allCores'.
It is now expressed as 'idle:epsilon:allCores' to properly model the
consumption of non-whole tasks on mono-core hosts. More info in the doc.

MSG:
- convert a new set of functions to the S4U C interface and move the old MSG
versions to legacy (MSG_process_self*, MSG_process_{un}ref, ...)

SMPI:
- Fortran bindings for DVFS have been removed.
- Add support for MPI_Irsend, MPI_Rsend, MPI_Rsend_init, MPI_Bsend,
MPI_Ibsend, MPI_Bsend_init, MPI_Buffer_attach, MPI_Buffer_detach
- SMPI can now be selected by cmake's find_module(MPI) with
MPI_C_COMPILER, MPI_CXX_COMPILER, MPI_Fortran_COMPILER variables.
- Add support for MPI Errhandlers in Comm, File or Win. Default errhandler is now
MPI_ERRORS_ARE_FATAL, so codes which were sending warnings may start failing.
- trace-call-location can be used with TI traces, and replayed, and is compatible
with smpi/comp-adjustment-file.
- sleep events are now correctly traced/replayed.
- Default for trace-call-location is now to use file names and not full paths.
To revert to previous behavior (in case of collision of filenames), option
"smpi/trace-call-use-absolute-path" can be set to yes.

Model-Checker:
- Use the included xxHash as an hash implem when C++14 is usable.
- Option model-checker/hash was removed. This is always activated now.
- New option smpi/buffering controls the MPI buffering in MC mode.
- MPI calls now MC_assert() that no MPI_ERR_* code is returned.
This is useful to check for MPI compliance.

Documentation:
- New section on plugins: how to define a new one, and existing ones.

XBT:
- xbt_mutex_t and xbt_cond_t are now marked as deprecated, a new C interface
on S4U is already available to replace them by sg_mutex_t and sg_cond_t.

XML:
- Introduce the <disk> tag as a replacement of the <storage>, <storage_type>,
and <mount> tags. The rationale is finish to decouple what should be handle
by SimGrid kernel (i.e., resources and activities) from plugins built in
user space (e.g., the file system plugin). This new tag currently accepts
only three attributes (id, read_bw, and write_bw). All the other information
that was declared with the storage related tags now has to be expressed as
properties. An example of platform using this new tag is available at
examples/platforms/hosts_with_disks.xml

tesh:
- 'expect signal' can now accept more than one potential signal.

Fixed bugs (FG.. -> framagit bugs; FG!.. -> framagit merge requests):
- FG28: add sg_actor_self (and other wrappers on this_actor methods)
- FG29 and FG33: provide a new C API to mutexes and condition variables
- FG30: convert MSG_process_{un}ref to sg_actor_{un}ref
- FG31: per-actor data
- FG34: SG_BARRIER_SERIAL_THREAD?
- FG35: model-checker does not like buster-produced binaries
- FG!13: MC: complete workaround in the error msg seen on modern systems
- FG!15: execute_flops now logs compute
- FG!16: Fix the ns-3 bindings when several flows are simultaneously finishing
- FG!17: ns-3: unblock the right number of communications + others issues
- FG!18: Improving the performance of the ns-3 bindings
- GH189: Energy consumption of parallel tasks
- GH219: Error in the throughput of TCP transfer
- GH!330: Minor polishing of English: Configuring_Simgrid
- GH!331: Fix a doc error about actors (Tutorial_algorithms)
- GH!332: Add '-O0' flag for: cmake -DCMAKE_BUILD_TYPE=Debug
- GH!334: Rework energy plugin, again

----------------------------------------------------------------------------

Documentation:
- Nicer introduction page.
- Migrate the "Deploy your application" page to the new doc.
- Move Java as a subtree of MSG.

General:
- Rename simgrid::TimeoutError to simgrid::TimeoutException.

XBT:
- Drop xbt_dynar_sort_strings().

Bugs:
- Really fix FG26: Turning off a link should raise NetworkFailureException
- FG27: Wrong exception thrown to wait_any when link is turned off
- GH328: Java: Canceling multiple tasks in a single vm/host

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The Exotic Solstice Release.

General:
- SunOS and Haiku OS support. Because exotic platforms are fun.
- Stop setting random seed with srand48() at initialization.
- Use addr2line as a fallback for stacktraces when backtrace is not available.
- Build option -Denable_documentation is now OFF by default.
- Network model 'NS3' was renamed into 'ns-3'.

Python:
- SimGrid can now hopefully be installed with pip.

S4U:
- wait_any can now be used for asynchronous executions too.

XBT:
- New log appenders: stdout and stderr. Use stdout for xbt_help.
- Drop xbt_dict_dump.

SMPI:
- SMPI now reports support of MPI3.1. This does not mean SMPI supports all MPI 3 calls, but it was already the case with 2.2
- MPI/IO is now supported over the Storage API (no files are written or read, storage is simulated). Supported calls are all synchronous ones.
- MPI interface is now const correct for input parameters
- MPI_Ireduce, MPI_Iallreduce, MPI_Iscan, MPI_Iexscan, MPI_Ireduce_scatter, MPI_Ireduce_scatter_block support
- Fortran bindings for async collectives.
- MPI_Comm_get_name, MPI_Comm_set_name, MPI_Count support.

Model-checker:
- Remove option 'model-check/record': Paths are recorded in any cases now.
- Remove option 'model-check/sparse-checkpoint': Checkpoints are now
always sparse. That's an immense gain in memory, and can even be
faster because of cache effects. So there is no need to clutter the
code to allow the user to go for the unefficient mode.

Network models:
- Remove the lagrange-based models (Reno/Reno2/Vegas). The regular
models proved to be more accurate than these old experiments.

Fixed bugs (FG=FramaGit; GH=GitHub -- Please prefer framagit for new bugs)
- FG1: Broken link in error messages
- FG2: missing installation documentation
- FG3: missing documentation in smpirun
- FG6: Python bindings not available on PyPI
- FG7: simple cmake call requires doxygen
- FG8: make python bindings an optional dependency
- FG10: Can not use MSG_process_set_data from SMPI any more
- FG11: Auto-restart actors forget their on_exit behavior
- FG12: -Denable_lto=OFF doesn't disable LTO
- FG13: Installs unstripped file 'bin/graphicator'
- FG14: Installs the empty directory 'doc/simgrid/html'
- FG15: Setting -Denable_python=OFF doesn't disable the search for pybind11
- FG17: Dead link in doc (pls_ns3)
- FG20: 'tesh --help' should return 0
- FG21: Documentation link on http://simgrid.org/ broken
- FG22: Debian installation instruction are broken
- FG26: Turning off a link should raise NetworkFailureException exceptions
- GH133: Java: a process can run on a VM even if its host is off
- GH320: Stacktrace: Avoid the backtrace variant of Boost.Stacktrace?
- GH326: Valgrind-detected error for join() when energy plugin is activated

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