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SST V16.0.0 Release Notes

SST V16.0.0 Release Notes
Fixed issues and significant code changes:

SST V16.0.0 Release Notes

General

This release contains several enhancements in checkpoint and the interactive debug capability.
A new element library, Carcosa, provides the ability to inject and model faults in conjunction with Vanadis and memHierarchy.
Several new capabilities have been ported from SST/macro to the mercury element library.

Deprecation and Removal Notices

SST-Elements is deprecating support for Ramulator and HMCSim as backends for MemHierarchy. Testing of these backends will be discontinued later this year. Note that Ramulator2 will continue to be supported.
Beginning in SST 17.0, statistics will no longer directly store their type in a string variable. Custom statistic types inheriting from StatisticBase must implement getStatisticTypeName(). This function will become pure virtual in 17.0. The function setStatisticTypeName() will also be removed as type names will become a property of the statistic type class rather than a per-statistic property.

Known Issues

There is an issue when using the Ubuntu 26 provided OpenMPI 5.0.10 as of this release. While simulations run correctly, the output is garbled so tests will not pass. We recommend using OpenMPI 4.1.x until this issue is resolved.

SST-Core

New Features and Enhancements

Changing SST’s partitioning when restarting from a checkpoint is now supported, provided the checkpoint was generated using SST’s serial (default) loading mechanism rather than parallel loading. If serial loading was used, you will see a graph configuration file in the top-level checkpoint directory.
The debug console now works in multi-rank and multi-threaded simulations as well as serial ones.
Significant enhancements were made to the debug console including:
- Users can navigate the object map, set watchpoints, etc. within a thread.
- The info command provides information on the thread being debugged and the thread command switches between threads in debugging.
- Added support for user-defined commands.
- The debugger is renamed from sst.interactive.simpledebug to sst.interactive.debugger.
Profiling output is unified so that it can be written to stdout and or a file (text or JSON). Use the --profiling-output flag to control the output destination and format. This includes data from profiling points, timing output (previously using the --print-timing-info flag), and resource usage.
JSON configuration files (both input and output) now support statistics, PortModules and arbitrarily nested subcomponents.

Notable Bug Fixes

Fixed error when using Python 3.14 with element python libraries.
Fixed bug in serializing maps using the SerOption::as_ptr_elem option. This resolves errors that showed up as intermittent checkpoint corruption. See sst-core issue #1592.

General updates, changes, and cleanup

Support for the previously deprecated TimeConverter pointers and non-checkpointable Handler types is removed.
If the checkpoint prefix provided on the command line is not valid, SST will now fail immediately with an error.
BaseComponent::getSimulationOutput() is now static.
Fixed various instances of uninitialized variables. These were not observed to be causing bugs but were fixed anyways.
Support for Python 3.8 and older is removed.
Changed links to have a globally unique identifier. This may cause a simulation output diff compared to SST 15.1 due to a one-time change in the sort criteria used to order events. The change supports repartitioned restarts and should broadly improve performance.
Improved JSON parser performance and cleaned up JSON configuration output generator.
The minimum supported autoconf version is now 2.69 when building from the repositories.
StatisticId_t is no longer derived from ComponentId_t.
General code clean up including: reducing string copies, replacement of lock_guard with scoped_lock, standardization such as =default; rather than empty default constructors/destructors.
Improved dangling and unused link error checks.
Added architecture and OS metadata to checkpoint manifest file.
Added warning for types that are automatically serialized due to being trivially serializable but cannot be mapped for debug.
Renamed simulation_impl to simulation.
Reorganized ConfigGraph files to a common location.
Added a new sst_mpi.h file which contains wrappers for MPI functions and eliminates the need for checking whether MPI is present throughout the rest of the Core.
Added ability to ignore configured library paths that include “_EXT_”. Intended for “extension” libraries that are used by components and loaded by SST-Core but do not, themselves, contain components. This fixed an issue where sst-info would fail in dlopen on these libraries.

Testing Framework updates

Deprecated functions were removed including many of the host_os_* functions and type-specific functions that read variables from SST configuration files. Use Python-provided functions to query the OS type and use the generic configuration file reading functions instead. Additionally, OSCommand, os_simple_command are replaced by os_command.
Fixed an MPI parameter that was incompatible with MPI 5.0.
Fixed detection of the Rocky Linux OS.
Added category decorators to control which subsets of tests run (pr, nightly, weekly).

SST-Elements

General updates
- Several elements have experimental checkpoint support added (see individual element release notes). This means the element is checkpointable but we are not yet actively testing the infrastructure and so it is prone to breakage. Testing is anticipated over the next few months.
- The minimum autoconf version is now 2.69 if building from the repository source.
balar
- Updated to operate solely on virtual addresses and let mmu/memHierarchy components manage address translation.
carcosa
- This is a new element that supports fault injection and modeling in conjunction with Vanadis.
cassini
- Added experimental checkpoint support.
iris
- Made improvements to SUMI libfabric provider and overall robustness.
memHierarchy
- TLBs (via the mmu library) can now be embedded in memHierarchy’s StandardInterface instead of needing to be a separate component.
- Fixed a race condition between a directory data writeback and a scraptchpad shootdown.
- Fixed an issue where the last subcomponent in the listener slot in caches did not get loaded.
- Added a hybrid backing mode for memory which combines a portion of memory backed using MMAP with a dynamically allocated range.
mercury
- Ported application environment features from SST/macro to support simulated applications with increased complexity (e.g., pthreads).
- Significantly refactored the component class hierarchy.
- Fixed an issue that caused sst-info to mistakenly attempt to dlopen some mercury support libraries. Installation of these libraryes was moved to SST_ELEMENT_LIBRARY_EXT_LIBDIR.
merlin
- Added experimental checkpoint support.
- Fixed dragonfly topology’s braodcast_to_groups to work for both absolute and relative global_route_mode.
- Fixed an off-by-one error in dragonfly group broadcast.
- Fixed merlin’s Python library System object to account for allocation_block_size when filling empty nodes with EmptyJob.
miranda
- Added experimental checkpoint support.
mmu
- Updated to work with memHierarchy as a TLB embedded in the memHierarchy interface.
- Cleaned up handling of page permissions.
- Added some serialization support but the library is not yet fully serializable (checkpointable).
- Renamed ports to match memHierarchy’s highlink/lowlink nomenclature.
- Added missing parameter documentation.
- Cleaned up types for thread IDs, page numbers, and page permissions.
- Fixed hard-coded line size to instead detect the cache line size from memHierarchy.
vanadis
- Cleaned up handling of page permissions.
- Cleaned up types for thread IDs, core IDs, and page numbers.
- Updated to always compile two versions of the vanadis element library, one with debug logging and one without. Components can be switched between the two by selecting the vanadis or vanadisdbg library in the input configuration. All vanadis components in a simulation should come from the same version of the library. The debug version is slower while the performance version provides limited output. The Vanadis core is renamed from dbg_VanadisCPU to simply core, although both names will work in SST 16.0.

SST-Macro

Updated for serialization, Handler, and TimeConverter pointer changes in SST-Core.
Updated cxxstd to 17.
Fixed an issue when using Python 3.13+.
As of SST 15.0, macro’s devel branch is no longer being kept in sync with sst-core’s devel branch. The master branches and releases will continue to be kept in sync. This means there may be times when the sst-macro and sst-core devel branches do not work together.

Fixed issues and significant code changes:

SST-Core

1354 Object map navigation in interactive console doesn’t work as expected for some containers

1376 Increase minimum required Python version from 3.6 to 3.9

1384 Enforce minimum Python version of 3.9

1466 remove warning about versions, since it isn’t really that useful and causes a strange Perl warning

1475 Move sst_ser_object() into private SST::Core::Serialization::pvt namespace

1476 Add flag to restore floating point precision for gcc

1477 Fix new/delete mismatches in address sanitizer

1480 SST debugger crashes when trying to print a component with a field that stores a null pointer

1481 Allow null pointers during debugging

1483 Support ObjectMap for std::bitset, std::vector, and std::atomic

1485 Reenable serialization of std::shared_ptr, making std::weak_ptr array serialization contingent on SST_SERIALIZE_WEAK_PTR_ARRAY macro

1486 Checkpoint Compatibility Check

1487 Support ObjectMap for std::tuple and std::pair

1488 Support ObjectMap for std::stack, std::queue, std::priority_queue

1489 Support ObjectMap for aggregates

1491 Reorganize ConfigGraph files

1492 Add ObjectMultimapCmp functor to sort ObjectMap entries numerically when possible

1493 Use const and final methods where possible

1495 Add missing #include

1496 Serialize pointers to std::tuple and std::pair, and make std::pair ObjectMap use first and second members

1497 Work around compiler bugs which suggest override when final is used without virtual

1498 Fix distribution so that elements can include configGraph.h

1499 Add ObjectMap support for SharedObject containers

1500 Add #include to places which use typeid()

1501 Clean up serialization mapper to use much less code

1503 Print bool values as true or false instead of 1 or 0

1504 Add ObjectMap support for std::optional and std::variant

1505 Fix for portChecks on nonlocal links

1508 Add ObjectMap support for std::unique_ptr

1509 Support ObjectMap for std::shared_ptr and std::weak_ptr

1510 Throw exceptions for unsupported mapping mode serializations

1513 Remove unnecessary call in Component mapping mode.

1514 Make complex numbers first-class ObjectMapFundamental objects

1515 Add warnings for trivially serializable types which cannot automatically have an ObjectMap created for them

1517 Rebuild ObjectMap at the beginning of every interactive session; add ObjectMap refresh() method

1518 Add clang-tidy script; make the least-impact changes found by clang-tidy

1521 Use =default for trivial constructors and destructors

1522 Use faster string find methods

1524 Use ‘std::scoped_lock’ instead of ‘std::lock_guard’

1525 Avoid unnecessary copies by using references

1526 Remove redundant std::move() calls which have no effect

1530 Pin Python version used in pre-commit GitHub Actions job

1531 Python upgrade causing some sst-core tests to fail on SLES systems

1533 Remove stale code in PyModel

1536 extend test times for tests counting heartbeats

1537 TimeConverter updates

1542 Change LinkId_t to 64-bits and create globally unique Link IDs

1547 Skip test on Rocky 10

1549 Event order update

1552 Add support for paging of output and max line length in interactive mode

1557 Add missing pop() in json parser

1560 Fix the bad MPI return codes

1562 Statistics are not output from restart actions

1564 Update and fix JSON parsing to pass core tests when translated to JSON

1566 Break StatisticId_t dependence on ComponentId_t

1567 Update minimum autoconf version to 2.69

1569 Link id update

1570 Unique link order

1571 Recalculate sync interval after init()

1572 Remote link discovery

1573 Add categorize decorator for controlling when tests run

1574 Disable checkpoint remap tests when MPI is not available.

1576 Rework the levels for verbose printing of execution information.

1577 Switch from Handler2 back to Handler

1579 Remove deprecated functions using TimeConverter* and rework internals to only use TimeConverter

1580 Final cleanup from move TimeConverter* to TimeConverter

1581 Remove deprecated functions and file from serialization

1582 Remove support for CPython < 3.9

1583 Fix Python 3.14 compatibility: segfaults in GC and module loader

1584 addLink calls use "port0" instead of "port"

1586 N2m restart

1587 Centralize profiling output from multiple sources

1588 PerfReporter contains MPI code despite building without MPI

1589 Added SST_MPI_Bcast, SST_MPI_Send, and SST_MPI_Recv to sst_mpi.h.

1590 Profile metadata

1591 Interactive Console for Parallel Debug

1592 Random segfault running test_MessageMesh_restart_smaller_ckpt_restart

1594 Test fixes for rocky and mypy

1595 Remove deprecated functions

1597 Skip test when running multiple ranks and threads

1602 Fix MPI parameter that causes failures in MPI 5.0.10

1603 Change BaseComponent::getSimulationOutput() to be static.

1604 Test framework categorization updates

1605 Update includes and copyrights

1606 header fixes MAC and SLES

1607 Simulation_impl -> Simulation

1608 Fix returning nullptr from function supposed to return std::string

1611 Fix warnings about whitespace in nlohmann_json operator definitions

1613 macOS 26 test fail following PR 1604

1614 Fix warnings in debugConsole when compiling without MPI

1617 Fixes for ThreadSanitizer

1618 Fix copy paste error in rankserial print

1619 Post delay sampling fix for parallel execution

1620 Ser as ptr fix

SST-Elements

1928 rdmaNic compilation error on devel

2561 Add checkpointing to Miranda

2567 MMU: Enable custom cache line sizes

2588 Squash compiler warnings

2592 Carcosa Element

2599 Mercury: major OperatingSystem refactor

2600 Merlin: test_nic parameter name mismatch

2604 MMU: Fix hardcoded line size and general cleanup

2605 Compile a debug and regular version of vanadis libraries.

2606 Mercury: Refactor NIC

2607 Mercury: move sleep methods to skeleton.h

2610 Dragonfly_untimed_broadcast_patch

2611 Ember: push some ESshmem tests off to Nightly

2613 Mercury: remove event library

2615 Seperated sleep calls into skeleton.cc file instead of included in skeleton.h.

2616 added a hybrid-backing mode to membackend backing

2619 Fixed the “listener” subcomponent slot of the Cache component from MemHierarchy

2620 MH.spad Reading issue(or bug?)

2621 MMU error checking and clean up

2625 MemH: Fix race between a scrtchpad shootdown and directory data writeback

2627 Event order update

2628 Update reference files found by nightlies for event order update.

2629 rdmaNic: Fix ref for sst-core ordering change

2632 Carcosa Interface Components

2633 Fixed basic_1node_1smp.py

2634 MemHierarchy TLB in interface

2636 Update testsuites for mask-mpi / Mercury

2637 Add Mercury pthread implementation and C compatibility fixes

2639 Update minimum autoconf version to 2.69

2645 mercury: build/test fixes

2646 Add missing setCpumask/setThreadId definitions and reassignCores virtual dispatch

2649 Handler2 to handler

2650 Remove call to os_simple_command()

2651 Fix dragonfly untimed broadcast_to_groups to work for both absolute and relative global_route_mode

2652 Final move from TimeConverter* to TimeConverter

2653 Switch from testing_check_is_nightly to categorize decorator on test methods

2654 Vanadis: Add missing test files to make-dist

2656 mercury libfabric/sumi and mv2 compatibility fixes

2658 OSCommand is deprecated and being removed

2659 Fixes for removed timeconverter pointer in golem and balar

2660 Add checkpoint for cassini library

2662 More Handler2 to Handler in TLB_Wrapper

2664 Initial experimental support for merlin checkpointing

2667 General compiler warning fixes. Mostly missing overrides and printf specifier mismatches.

2668 updated Carcosa file names/naming to match sst-elements conventions

2669 Fix GCC 15 and Apple Clang 21 compiler warnings

2671 Update copyright dates except carcosa

2672 Copyright updates for carcosa

2674 Fix warnings about whitespace in nlohmann_json operator definitions

2676 Ramulator2 config has been broken

2677 Fix testBackendRamulator2 again

2678 Fix testBackendRamulator2

2679 Update ramulator2 ref file

SST-Macro

732 Replace deprecated PyEval_CallObject call

738 Version and date updates for release

742 Update for upcoming SST 16 Release

745 Update sst-dumpi submodule

748 Release updates