SimGrid (3.28.1) NOT RELEASED YET (v3.29 expected September 22. 2021, 19:21 UTC)
-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
-
-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.
+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; 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
versions. Sorry for the inconvenience.
- Dynamic network factors: users can configure a callback to define
the network factors dynamically. This API is available at
- simgrid::kernel::resource::NetworkModelIntf.
+ simgrid::kernel::resource::NetworkModelIntf.
- Users have access to complete information about the current communication
to decide which factor to apply. This includes: message size, source and
- destination hosts, links and zones traversed.
+ destination hosts, links and zones traversed.
- Dynamic factors for both latency and bandwidth.
- For more details, see the example in (examples/cpp/network-factors).
+ - Plugin host_energy: the "watt_off" and "watt_per_state" host properties,
+ deprecated since version 3.24, are no longer supported. Instead, use
+ "wattage_off" and "wattage_per_state".
XBT:
- xbt_assert is not disabled anymore, even when built with enable_debug=off.
