+SimGrid (3.30) January 30. 2022.
+
+The Sunday Bloody Sunday release.
+
+Main user-visible changes:
+ - The SimDag API for the simulation of the scheduling of Directed Acyclic
+ Graphs has been dropped. It was marked as deprecated for a couple of years.
+ We finally complete the implementation of what has been called SimDag++
+ internally, i.e., porting the different features of SimDag on top of S4U.
+ The new way to simulate the execution of dependent activities directly by
+ maestro (without any other actor) is details in the examples/cpp/dag-* series
+ of examples.
+ - The removal of SimDag led us to also remove the export to Jedule files that
+ was tightly coupled to SimDag. The instrumentation of DAG simulation is still
+ possible through the regular instrumentation API based on the Paje format.
+ - We also dropped the old and clumsy Lua bindings to create platforms in a
+ programmatic way. It can be done in C++ in a much cleaner way now, which
+ motivates this suppression.
+
+S4U:
+ - Introduce on_X_cb() functions for all signals, to attach a new
+ callback to the signal X. The signal variables are now hidden and
+ only these functions should be used.
+ Rationale: this enables the usual deprecation scheme where functions
+ remain for 4 releases if we need to modify the signals, while the
+ current code with the signal variables directly visible prevents any
+ smooth transition.
+ - New function: Engine::run_until(date), to split the simulation.
+ - New signal: Activity::on_veto, to detect when an activity fails to start.
+ - Signal change: Comm::on_start(Comm&, bool) has been replaced by
+ Comm::on_send and Comm::recv. These two signals respectively correspond to
+ when the sending or receiving side of a Comm is ready. They are raised at
+ the same locations as the former Comm::on_start signal.
+ - New function: Engine::track_vetoed_activities() to interrupt run()
+ when an activity fails to start, and to keep track of such activities.
+ Please see the corresponding example for more info.
+ - New functions: s4u::Comm::{sendto_init, set_source, set_destination} to enable
+ the use of vetoers with direct host-to-host communications. Both source and
+ destination have to set for a comm to start. Each call to these setters check
+ if all vetoes are satisfied. When it is the case, the comm starts. A use case of
+ these functions is given in examples/cpp/dag-scheduling.
+ - New functions: {Exec, Io}::update_priority allow you to modify the priority of
+ these kinds of activities during their execution. Behavior is detailed in
+ examples/cpp/io-priority/.
+
+SMPI:
+ - Dynamic costs for MPI operations: New API to allow users to dynamically
+ change injected costs for MPI_Recv, MPI_Send and MPI_Isend operations.
+ Alternative for smpi/or, smpi/os and smpi/ois configuration options.
+ - Fix some issues with the replay mechanism.
+
+XBT:
+ - Function xbt::Extendable::get_data() is now templated with the type of the
+ pointee. Untyped function is deprecated. Use get_data<void>() if you still
+ want to retrieve void*.
+
+Documentation:
+ - New section: "SimGrid MPI calibration of a Grid5000 cluster"
+ presenting how to properly calibrate MPI communications in SimGrid.
+ - Complete and reword the platform section, which is now completed.
+
+Python:
+ - Thread contexts are used by default with Python bindings. Other kinds of
+ contexts revealed unstable, specially starting with pybind11 v2.8.0.
+
+Fixed bugs (FG#.. -> FramaGit bugs; FG!.. -> FG merge requests)
+ (FG: issues on Framagit; GH: issues on GitHub)
+ - FG#95: Wrong computation time for multicore execution after pstate change
+ - FG#97: Wrong computation time for ptask+multicore+pstates
+ - FG#98: SMPI offline simulation is inconsistent with the online simulation
+ (deadlocks / message truncation)
+ - FG#99: Weird segfault when not sealing an host
+
+----------------------------------------------------------------------------
+
+SimGrid (3.29) October 7. 2021
+
+The "Ask a stupid question" release.
+
+We wish that every user ask one question about SimGrid to celebrate.
+On Mattermost, Stack Overflow or using the issues tracker.
+
+
+New modeling features:
+ - Non-linear resource sharing, modeling resources whose performance heavily degrades with contention:
+ - The total capacity may be updated dynamically through a callback
+ and depends mainly on the number of concurrent flows.
+ - Examples (both cpp and python): io-degradation, network-nonlinear, exec-cpu-nonlinear
+
+ - Dynamic factors: model variability in the speed of activities
+ - Each action can now have a factor that affects its progression.
+ This multiplicative factor is applied when updating the amount of work
+ remaining, thereby an activity with factor=0.5 only uses half of the
+ instantaneous power/bandwidth it is allocated and will appear twice
+ slower than what it actually consumes.
+ - This can be used to model a overhead (e.g., there is a 20 bytes
+ header in a 480 bytes TCP packet so the factor 0.9583) but the novelty
+ is this factor can now easily be adjusted depending on activity's and
+ resources characteristics.
+ - This existed for network (e.g., the effective bandwidth depends
+ on the message in SMPI piecewise-linear network model) but it is now
+ more general (the factor may depend on the source and destination and
+ thus account to different behaviors for intra-node communications and
+ extra-node communications) and is available for CPUs (e.g., if you
+ want to model an affinity as in the "Unrelated Machines" problem in
+ scheduling) and disks (e.g., if you want to model a stochastic
+ capacity) too.
+ - For that, resources can be provided with a callback that computes
+ the activity factor when creating the action.
+ - Example: examples/cpp/exec-cpu-factors
+ - The same mechanism is also available for the latency, which
+ allows to easily introduce complex variability patterns.
+
+Python:
+ - Added support to programmatic platform creation in Python.
+ Example: examples/python/clusters-multicpu
+
+S4U:
+ - Disk and Host now have a set_sharing_policy() too, for non-linear sharing.
+ This can only be set through the API, not through XML files.
+
+SMPI:
+ - TI Tracing/Replay:
+ - Multiple fixes to ensure reproducibility of tracing
+ - scan/excan can now be replayed
+ - wait action now uses ranks and not pid, as the other ones.
+ - smpi/init and smpi/finalization-barrier are now valid for replays.
+ - exit() is now intercepted by SMPI to avoid premature shutdown of
+ simulation. First non 0 return codes is returned as simulation return
+ code.
+
+Documentation:
+ * New section "Release Notes" documenting recent and current developments.
+ * New section "Modeling I/O: the realistic way" presenting how to properly model disks in SimGrid.
+ * Improvements in API Reference for C++ and Python interfaces.
+
+ns-3 model:
+ - Make wifi creation compatible with ns-3 version 3.34 too.
+
+Fixed bugs (FG#.. -> FramaGit bugs; FG!.. -> FG merge requests)
+ (FG: issues on Framagit; GH: issues on GitHub)
+ - FG#77: Search feature of doc is broken (update sphinx theme version)
+ - FG#78: Multiple fixes for SMPI replay:
+ - TI tracing of allotallv/w was outputting wrong values
+ - MPI_LOGICAL in fortran is actually 32 bits wide, and not 8.
+
+----------------------------------------------------------------------------
+
+SimGrid (3.28) July 14. 2021
+
+The Victoriadagarna Release.
