X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/c70c4fc96f1007cc65e32f813ea9afa433a6650e..37872cead9e0267ec88aa7655d5aa1b43ea72a95:/ChangeLog

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-SimGrid (3.28.1) NOT RELEASED YET (v3.29 expected September 22. 2021, 19:21 UTC)
+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.
 
-New features:
- - Non-linear resource sharing: allows to dynamically change the resource
-   capacity. Users can change this capacity by setting a callback which will
-   be called when SimGrid is sharing the resource between the active
-   activities. An activity can be a task running, a read/write IO operation or a
-   communication flow.
-   - Callback signature: double (double capacity, int n_activities): given the
-     current resource's capacity and number of activities running on it,
-	 returns the new capacity.
-   - Note that this callback is in the critical path of the system solve and
-   should not take long to execute.
-   - Examples:
-     - Disk: examples/cpp/io-degradation
-	 - Link: examples/cpp/network-nonlinear
-	 - CPU: examples/cpp/exec-cpu-nonlinear
- - Dynamic factors for CPU and disk: similarly to dynamic network factors,
- allows the user to set a callback which can affect the progress of activities
- (multiplicative factor applied when updating the amount of work remaining).
-   - Example: examples/cpp/exec-cpu-factors
+Python:
+ - Added support to programmatic platform creation in Python.
+   Example: examples/python/clusters-multicpu
 
 S4U:
- - New: s4u::Disk::set_sharing_policy() and s4u::Host::set_sharing_policy().
-   Allows the configuration of non-linear resource sharing for hosts and
-   disks.
+ - 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.
+  * 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; GF: issues on GForge; GH: issues on GitHub)
+ - 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.
+ - FG#77: Search feature of doc is broken (update sphinx theme version)
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 SimGrid (3.28) July 14. 2021