Skip to content

Latest commit

 

History

History
979 lines (693 loc) · 36.7 KB

release.rst

File metadata and controls

979 lines (693 loc) · 36.7 KB
Raw

Release notes

Release 1.118.0

New features

  1. New supported platforms:

    • lia6gc (Linux, ARM64, GCC).
    • lia6ll (Linux, ARM64, Clang/LLVM).
    • xca6ll (macOS, ARM64, Clang/LLVM).

    See :ref:`topic-platform-limitations` for limitations in the support for Apple Hardened Runtime on xca6ll.

  2. Support removed for platform:

    • xci3ll (macOS, IA-32, Clang/LLVM).

    Support for this platform was removed in macOS 10.15 (Catalina), making it inconvenient to develop and test.

  3. The arena's :term:`spare commit limit` is now expressed as a fraction of the :term:`committed <mapped>` memory (rather than a fixed size, as previously). This allows the :term:`spare committed memory` to scale with the :term:`working set` size. Set the spare commit limit using the keyword argument :c:macro:`MPS_KEY_SPARE` to :c:func:`mps_arena_create_k`, or the function :c:func:`mps_arena_spare_set`, and query it using the function :c:func:`mps_arena_spare`.

  4. A new support tool, the monitor, implements a graphical user interface for analysis of :ref:`topic-telemetry`. This is experimental: the implementation is likely to change in future versions of the MPS. See :ref:`design-monitor`.

  5. The newly-public transforms feature updates references to a set of objects throughout the automatically managed portion of the heap, allowing them to be replaced by new versions. See :ref:`topic-transform`.

  6. The new function :c:func:`mps_pool_walk` visits all areas of :term:`formatted objects` in a pool using the :ref:`topic-scanning-protocol`, support hot reloading and serialization. See :ref:`design-walk`.

  7. An :term:`allocation point` for a pool belonging to the class :ref:`pool-amc` can now be configured so that allocations do not provoke garbage collections, reducing the amount of re-hashing for address-based hash tables using :term:`location dependency`. See :ref:`pool-amc-hash-arrays`.

  8. The new function :c:func:`mps_addr_object` allows clients to discover the base pointer of an object from a pointer to anywhere inside the object. This is intended to support stack tracing and debugging for client programs that allocate their code on the heap.

  9. A :term:`virtual memory arena` can now be configured to call functions when it acquires a new chunk of :term:`address space`, and when it returns a chunk of address space to the operation system. This is intended to support dynamic function tables in Windows. See :ref:`topic-arena-extension`.

Interface changes

  1. The deprecated pool class MV (Manual Variable), and the deprecated functions mps_mv_free_size and mps_mv_size have been removed. Use :ref:`pool-mvff` and the generic functions :c:func:`mps_pool_free_size` and :c:func:`mps_pool_total_size` instead.
  2. The deprecated function :c:func:`mps_tramp` has been removed. The MPS has had no need for a trampoline, and client programs have not needed to take any special precautions before calling functions in the MPS, since version 1.111.
  3. The deprecated functions :c:func:`mps_arena_expose`, :c:func:`mps_arena_unsafe_expose_remember_protection` and :c:func:`mps_arena_unsafe_expose_restore_protection` have been removed. If you need access to protected memory for debugging a fatal error, use :c:func:`mps_arena_postmortem` instead.
  4. The deprecated reservoir functions :c:func:`mps_ap_fill_with_reservoir_permit`, :c:func:`mps_reservoir_available`, :c:func:`mps_reservoir_limit`, :c:func:`mps_reservoir_limit_set` and :c:func:`mps_reserve_with_reservoir_permit`, have been removed.
  5. The deprecated function :c:func:`mps_fix` has been removed. Use the macro :c:func:`MPS_FIX12` instead.
  6. The deprecated function :c:func:`mps_telemetry_control` has been removed. Use :c:func:`mps_telemetry_get`, :c:func:`mps_telemetry_set` and :c:func:`mps_telemetry_reset` instead.
  7. The keyword argument MPS_KEY_SPARE_COMMIT_LIMIT to :c:func:`mps_arena_create_k`, and the functions :c:func:`mps_arena_spare_commit_limit` and :c:func:`mps_arena_spare_commit_limit_set` are now deprecated. Use :c:macro:`MPS_KEY_SPARE`, :c:func:`mps_arena_spare` and :c:func:`mps_arena_spare_set` instead.
  8. The format of the :term:`telemetry stream` has changed: Booleans are no longer packed into bitfields, but are emitted as unsigned bytes. This makes it possible to decode the telemetry stream using the Python function |unpack|_.
  9. The functions :c:func:`mps_formatted_objects_walk` and :c:func:`mps_amc_apply` are deprecated in favour of the new function :c:func:`mps_pool_walk`.

Other changes

  1. On FreeBSD and Linux, if the MPS handles a signal while the client program is blocked in a system call, the system call is automatically restarted and does not fail with EINTR. See :ref:`topic-thread-signal`.
  2. On FreeBSD and Linux, the MPS signal handlers no longer modify errno. See GitHub issue #10.
  3. The MPS now builds with Clang 10 and -Wimplicit-int-float-conversion. See GitHub issue #51.
  4. The MPS now builds with clang -Wcomma. See GitHub issue #47.

Release 1.117.0

New features

  1. On FreeBSD, Linux and macOS, the MPS is now able to run in the child process after fork(). See :ref:`topic-thread-fork`.
  2. The MPS now supports Windows Vista or later; it no longer supports Windows XP. (Microsoft's own support for Windows XP expired in April 2014.) This is so that we can use InitOnceExecuteOnce() to ensure thread-safe initialization.

Interface changes

  1. The pool class MV (Manual Variable) is now deprecated.

Other changes

  1. References from the MPS's own stack frames no longer :term:`pin <pinning>` objects allocated by the :term:`client program` in moving pools, which prevented them from moving. See job003525.
  2. Creation of :term:`arenas` is now thread-safe on Windows. See job004056.
  3. :ref:`pool-awl` and :ref:`pool-lo` pools now detect (and assert on) invalid :term:`exact references`. See job004070.
  4. The MPS now compiles without warnings on GCC version 7 with -Wextra. See job004076.
  5. Deprecated function :c:func:`mps_arena_roots_walk` no longer causes :c:func:`mps_arena_formatted_objects_walk` to miss some objects. See job004090.

Release 1.116.0

New features

  1. The MPS now measures the mortality of a :term:`generation` each time it is :term:`collected`, and maintains a moving average. This means that it is no longer important to provide an accurate estimate of the mortality when creating a :term:`generation chain` by calling :c:func:`mps_chain_create`.
  2. The MPS no longer supports Linux 2.4 and 2.5. (These versions used LinuxThreads instead of POSIX threads; all major distributions have long since ceased to support these versions and so it is no longer convenient to test against them.) See :ref:`guide-overview-platforms`.
  3. New function :c:func:`mps_arena_postmortem` assists with postmortem debugging.
  4. New function :c:func:`mps_arena_busy` assists debugging of re-entry errors in dynamic function table callbacks on Windows on x86-64.

Interface changes

  1. The pool class :ref:`pool-snc` is no longer deprecated.
  2. Allocation frames are no longer deprecated. See :ref:`topic-frame`.
  3. On Linux and FreeBSD, it is now possible to configure the signals used to suspend and resume threads. See :ref:`topic-thread-signal`.

Other changes

  1. It is now possible to register a :term:`thread` with the MPS multiple times on OS X, thus supporting the use case where a program that does not use the MPS is calling into MPS-using code from multiple threads. (This was already supported on other platforms.) See job003559.
  2. The function :c:func:`mps_arena_formatted_objects_walk` walks the :term:`formatted objects` in all :term:`pools`. Previously this was not implemented for :ref:`pool-ams` pools. See job003738.
  3. Objects in :ref:`pool-snc` pools are no longer scanned after their :term:`allocation frame` is popped, and so do not keep objects in automatically managed pools alive. See job003883.
  4. When the MPS :term:`collects` a set of :term:`generations`, it :term:`condemns <condemned set>` only the :term:`blocks` in those generations. Previously, it also condemned blocks that happened to share a region of memory with blocks currently or formerly allocated in those generations. See job004000.
  5. Memory in :term:`allocation points` no longer contributes to the decision to start a :term:`garbage collection`, avoiding wasted work repeatedly collecting generations with very small capacities. See job004007.
  6. The MPS no longer considers :term:`collecting <collect>` the world again, without allowing the :term:`client program` to run first. See job004011.
  7. :term:`Roots` created by :c:func:`mps_root_create_thread_scanned` no longer cause an assertion failure. See job004036.
  8. The MPS test suite now compiles and passes with GCC 6.1. See job004037.
  9. The MPS no longer passes an uninitialized variable to :c:func:`thread_swap_exception_ports` on OS X. See job004040.

Release 1.115.0

New features

  1. The MPS now provides control over the maximum time that operations within an arena may pause the :term:`client program` for. This can be specified by the new function :c:func:`mps_arena_pause_time_set` or by passing the new keyword argument :c:macro:`MPS_KEY_PAUSE_TIME` to :c:func:`mps_arena_create_k`. The current value can be retrieved by the new function :c:func:`mps_arena_pause_time`.

    The maximum pause time defaults to 0.1 seconds. For the old behaviour (whereby the MPS always returned to the :term:`client program` as soon as possible), set it to zero.

  2. New supported platforms fri3ll (FreeBSD, IA-32, Clang/LLVM) and fri6ll (FreeBSD, x86-64, Clang/LLVM).

  3. When creating an :ref:`pool-amc` pool, :c:func:`mps_pool_create_k` accepts the new keyword argument :c:macro:`MPS_KEY_EXTEND_BY`, specifying the minimum size of the memory segments that the pool requests from the :term:`arena`.

  4. The function :c:func:`mps_arena_create_k` accepts two new :term:`keyword arguments`. :c:macro:`MPS_KEY_COMMIT_LIMIT` sets the :term:`commit limit` for the arena, and MPS_KEY_SPARE_COMMIT_LIMIT sets the :term:`spare commit limit` for the arena.

  5. New area scanning functions :c:func:`mps_scan_area`, :c:func:`mps_scan_area_masked`, :c:func:`mps_scan_area_tagged`, :c:func:`mps_scan_area_tagged_or_zero` for use when scanning, especially when scanning threads and :term:`tagged references`.

  6. New thread root functions :c:func:`mps_root_create_thread`, :c:func:`mps_root_create_thread_tagged`, and :c:func:`mps_root_create_thread_scanned` allow flexible scanning of thread stacks and registers in any format, with convenient implementations provided for :term:`tagged references`.

  7. New function :c:func:`mps_root_create_table_tagged` for tables of roots containing :term:`tagged references`.

  8. New area root functions :c:func:`mps_root_create_area` and :c:func:`mps_root_create_area_tagged` for areas of memory that can be scanned by area scanning functions.

Interface changes

  1. The pool class MV (Manual Variable) is no longer deprecated.
  2. The type of pool classes is now :c:type:`mps_pool_class_t`. The old name :c:type:`mps_class_t` is still available via a typedef, but is deprecated.
  3. The functions mps_mv_free_size, mps_mv_size, :c:func:`mps_mvff_free_size`, :c:func:`mps_mvff_size`, :c:func:`mps_mvt_free_size` and :c:func:`mps_mvt_size` are now deprecated in favour of the generic functions :c:func:`mps_pool_free_size` and :c:func:`mps_pool_total_size`.
  4. The function :c:func:`mps_root_create_reg` is deprecated in favour of :c:func:`mps_root_create_thread_tagged`.
  5. The function :c:func:`mps_root_create_table_masked` is deprecated in favour of :c:func:`mps_root_create_table_tagged`.
  6. The :ref:`pool-snc` pool class now implements :c:func:`mps_pool_total_size` and :c:func:`mps_pool_free_size`.
  7. The (undocumented) reservoir functions :c:func:`mps_ap_fill_with_reservoir_permit`, :c:func:`mps_reservoir_available`, :c:func:`mps_reservoir_limit`, :c:func:`mps_reservoir_limit_set`, and :c:func:`mps_reserve_with_reservoir_permit`, together with the has_reservoir_permit arguments to :c:func:`mps_sac_alloc` and :c:func:`MPS_SAC_ALLOC_FAST` are now deprecated.

Other changes

  1. :c:func:`mps_arena_committed` now returns a meaningful value (the amount of memory marked as in use in the page tables) for :term:`client arenas`. See job001887.
  2. :ref:`pool-amc` pools now assert that exact references into the pool are aligned to the pool's alignment. See job002175.
  3. Internal calculation of the address space available to the MPS no longer takes time proportional to the number of times the arena has been extended, speeding up allocation when memory is tight. See job003814.
  4. Setting :c:macro:`MPS_KEY_SPARE` for a :ref:`pool-mvff` pool now works. See job003870.
  5. In the :term:`hot` (production) variety, :c:func:`mps_pool_free_size` now returns the correct result for :ref:`pool-awl` and :ref:`pool-lo` pools. See job003884.
  6. When the arena is out of memory and cannot be extended without hitting the :term:`commit limit`, the MPS now returns :c:macro:`MPS_RES_COMMIT_LIMIT` rather than substituting :c:macro:`MPS_RES_RESOURCE`. See job003899.
  7. Unfinalizable objects can no longer be registered for finalization. Previously the objects would be registered but never finalized. See job003865.
  8. :c:func:`mps_arena_has_addr` now returns the correct result for objects allocated from the :ref:`pool-mfs`, MV (Manual Variable), and :ref:`pool-mvff` pools. See job003866.
  9. The MPS can now make use of :term:`spare committed memory` even if it is :term:`mapped` at an unhelpful address, by unmapping it and remapping at a better address. See job003898.
  10. :c:func:`mps_arena_step` now always considers starting a new :term:`garbage collection` if the remaining idle time is long enough to complete it. (Previously, if there was already a collection in progress when :c:func:`mps_arena_step` was called, it would finish the collection but not consider starting a new one.) See job003934.
  11. The MPS no longer carries out :term:`garbage collections` when there is no collection work to be done. See job003938.
  12. The MPS is less aggressive in its use of hardware memory protection to maintain :term:`write barrier` to speed up future collections. This is particularly important for OS X, where memory protection operations are very expensive. See job003371 and job003975.
  13. The MPS coalesces memory protection, reducing the number of system calls. This markedly improves real run time on operating systems where memory protection operations are very expensive, such as OS X, but also has a significant effect on Linux. See job003371 and job003975.

Release 1.114.0

New features

  1. :term:`Ambiguous <ambiguous reference>` :term:`interior pointers` now keep objects in :ref:`pool-amc` and :ref:`pool-amcz` pools alive.

    This means that if the compiler optimizes away a pointer to the base of an object, leaving an interior pointer as the only reference keeping the object alive, this does not cause the object to be incorrectly collected. Or, if you are writing your own compiler, you can now perform such an optimization safely.

    If you require the old behaviour (in which ambiguous interior pointers were ignored) then you can set the :c:macro:`MPS_KEY_INTERIOR` keyword argument to FALSE when calling :c:func:`mps_pool_create_k`.

  2. The logic for deciding which generations should be collected has changed. Now, a chain may be scheduled for collection if the new size of any of its generations exceeds its capacity, and when a chain is collected, all generations are collected up to, and including, the highest generation whose new size exceeds its capacity. This ensures that all generations are collected reliably on chains where there is no allocation into the nursery generation. See :ref:`topic-collection-schedule`.

    (Previously, only the nursery generation in each chain was considered, and a chain was collected up to, but not including, the lowest generation whose new size was within its capacity.)

    As a result of this change, we recommend that you retune your generation sizes. (This is not necessary, but may improve performance.)

  3. New pool introspection functions :c:func:`mps_pool_free_size` and :c:func:`mps_pool_total_size`.

Interface changes

  1. The granularity with which the arena manages memory can now be specified using the :c:macro:`MPS_KEY_ARENA_GRAIN_SIZE` keyword argument to :c:func:`mps_arena_create_k`. See :c:func:`mps_arena_class_cl` and :c:func:`mps_arena_class_vm`.
  2. There is now a default value (currently 256 :term:`megabytes`) for the :c:macro:`MPS_KEY_ARENA_SIZE` keyword argument to :c:func:`mps_arena_create_k` when creating a virtual memory arena. See :c:func:`mps_arena_class_vm`.
  3. The keyword argument :c:macro:`MPS_KEY_AMS_SUPPORT_AMBIGUOUS` now defaults to TRUE in order to better support the general case: the value FALSE is appropriate only when you know that all references are exact. See :ref:`pool-ams`.
  4. There is now a default value for the :c:macro:`MPS_KEY_AWL_FIND_DEPENDENT` keyword argument to :c:func:`mps_pool_create_k` when creating an :ref:`pool-awl` pool. The default value is a function that always returns NULL (meaning that there is no dependent object).
  5. It is now possible to configure the alignment of objects allocated in an MV (Manual Variable) pool, by passing the :c:macro:`MPS_KEY_ALIGN` keyword argument to :c:func:`mps_pool_create_k`.
  6. The :ref:`pool-mvff` pool class takes a new keyword argument :c:macro:`MPS_KEY_SPARE`. This specifies the maximum proportion of memory that the pool will keep spare for future allocations.
  7. The alignment requirements for :ref:`pool-mvff` and :ref:`pool-mvt` pools have been relaxed on the platforms w3i3mv and w3i6mv. On all platforms it is now possible to specify alignments down to sizeof(void *) as the alignment for pools of these classes.
  8. The sizes of the templates in a :c:type:`mps_pool_debug_option_s` structure no longer have to be related to the alignment of the pools that they are used with. This makes it easier to reuse these structures.

Other changes

  1. The :ref:`pool-ams` pool class no longer triggers the assertion !AMS_IS_INVALID_COLOUR(seg, i) under rare circumstances (namely, detaching an :term:`allocation point` from a :term:`grey` segment when :c:macro:`MPS_KEY_AMS_SUPPORT_AMBIGUOUS` is FALSE). See job001549.
  2. :c:func:`mps_arena_roots_walk` no longer triggers an assertion failure when run twice in succession. See job003496.
  3. The alignment of :ref:`pool-awl` pools is now configurable via the object format, as documented, and is no longer always :c:macro:`MPS_PF_ALIGN`. See job003745.
  4. The debugging version of the :ref:`pool-mvff` pool class, :c:func:`mps_class_mvff_debug`, no longer triggers an assertion failure if you allocate a large object. See job003751.
  5. :program:`mpseventtxt` now successfully processes a telemetry log containing multiple labels associated with the same address. See job003756.
  6. :ref:`pool-ams`, :ref:`pool-awl` and :ref:`pool-lo` pools get reliably collected, even in the case where the pool is the only pool on its generation chain and is allocating into some generation other than the nursery. See job003771.
  7. Allocation into :ref:`pool-awl` pools again reliably provokes garbage collections of the generation that the pool belongs to. (In version 1.113, the generation would only be collected if a pool of some other class allocated into it.) See job003772.
  8. All unreachable objects in :ref:`pool-lo` pools are finalized. (Previously, objects on a segment attached to an allocation point were not finalized until the allocation point was full.) See job003773.
  9. The :ref:`pool-mvt` and :ref:`pool-mvff` pool classes are now around 25% faster (in our benchmarks) than they were in version 1.113.
  10. The default assertion handler in the default :term:`plinth` now flushes the telemetry stream before aborting. See :c:func:`mps_lib_assert_fail`.
  11. Garbage collection performance is substantially improved in the situation where the arena has been extended many times. Critical operations now take time logarithmic in the number of times the arena has been extended (rather than linear, as in version 1.113 and earlier). See job003554.

Release 1.113.0

New features

  1. In previous releases there was an implicit connection between blocks allocated by :ref:`pool-awl` and :ref:`pool-lo` pools, and blocks allocated by other automatically managed pool classes.

    In particular, blocks allocated by AWL and LO pools were garbage collected together with blocks allocated by :ref:`pool-ams` pools, and blocks allocated by :ref:`pool-amc` pools in generation 1 of their chains.

    This is no longer the case: to arrange for blocks to be collected together you need to ensure that they are allocated in the same generation chain, using the :c:macro:`MPS_KEY_CHAIN` and :c:macro:`MPS_KEY_GEN` keyword arguments to :c:func:`mps_pool_create_k`.

    So if you have code like this:

    res = mps_pool_create(&my_amc, arena, mps_class_amc(), my_chain);
res = mps_pool_create(&my_awl, arena, mps_class_awl());

    and you want to retain the connection between these pools, then you must ensure that they use the same generation chain:

    MPS_ARGS_BEGIN(args) {
  MPS_ARGS_ADD(args, MPS_KEY_CHAIN, my_chain);
  res = mps_pool_create_k(&my_amc, arena, mps_class_amc(), args);
} MPS_ARGS_END(args);

MPS_ARGS_BEGIN(args) {
  MPS_ARGS_ADD(args, MPS_KEY_CHAIN, my_chain);
  MPS_ARGS_ADD(args, MPS_KEY_GEN, 1);
  res = mps_pool_create_k(&my_awl, arena, mps_class_awl(), args);
} MPS_ARGS_END(args);

Interface changes

  1. When creating a list of keyword arguments, there is no longer any need to call :c:func:`MPS_ARGS_DONE`. See :ref:`topic-keyword`.
  2. When creating an automatically managed pool using :c:func:`mps_pool_create_k`, it is no longer necessary to pass in a generation chain. The arena has a default generation chain and this is used by all automatically managed pools where no generation chain was specified.
  3. It is now possible to specify a generation chain for :ref:`pool-awl` and :ref:`pool-lo` pool classes, by using the optional :c:macro:`MPS_KEY_CHAIN` keyword argument to :c:func:`mps_pool_create_k`.
  4. It is now possible to specify which generation the :ref:`pool-ams`, :ref:`pool-awl`, and :ref:`pool-lo` pool classes allocate new objects into, using the optional :c:macro:`MPS_KEY_GEN` keyword argument to :c:func:`mps_pool_create_k`.

Other changes

  1. The MPS now retains some unused memory instead of returning it to the operating system. This reduces unnecessary overhead due to system calls, thrashing the operating system's page table, and zeroing memory when re-allocated. See job003700.

Release 1.112.0

New features

  1. New supported platform lii6ll (Linux, x86-64, Clang/LLVM).
  2. On Windows, you can now request that the MPS allocate address space from the top down, allowing a 32-bit executable linked with /LARGEADDRESSAWARE to use the top half of the address space. Use the keyword argument :c:macro:`MPS_KEY_VMW3_TOP_DOWN` when creating an arena of class :c:func:`mps_arena_class_vm`.
  3. On OS X, multi-threaded programs are now supported. See :ref:`topic-thread`.
  4. On OS X, you can now debug the MPS using lldb.

Interface changes

  1. In the :term:`hot` (production) variety, the default assertion handler now prints messages to standard error but does not terminate the program. Even though assertions indicate serious problems in the program, an end-user does not always want an application to terminate when there is a chance to shut down safely and save work, or even to limp along indefinitely. See :ref:`topic-error-assertion-handling`.

  2. The behaviour when an assertion is triggered is now configurable in the default :term:`plinth` by installing an assertion handler. See :c:func:`mps_lib_assert_fail_install`.

  3. Functions that take a variable number of arguments (:c:func:`mps_arena_create`, :c:func:`mps_pool_create`, :c:func:`mps_ap_create`) and their va_list alternatives (:c:func:`mps_arena_create_v` etc.) are now deprecated in favour of functions that use a :term:`keyword argument` interface (:c:func:`mps_arena_create_k`, :c:func:`mps_pool_create_k`, :c:func:`mps_ap_create_k`).

    Similarly, the object format variant structures (:c:type:`mps_fmt_A_s` etc.) and the functions that take them as arguments (:c:func:`mps_fmt_create_A` etc.) are now deprecated in favour of :c:func:`mps_fmt_create_k`.

    The new interfaces provide better reporting of errors, default values for arguments, and forward compatibility. See :ref:`topic-keyword`.

    The old interfaces continue to be supported for now, but new features will become available through the keyword interface only.

  4. :ref:`pool-mfs` pools no longer refuse to manage blocks that are smaller than the platform alignment. They now round up smaller sizes internally if necessary.

  5. :ref:`pool-mvt` pools now allow the client to specify the alignment of blocks. Use the keyword argument :c:macro:`MPS_KEY_ALIGN` when creating a pool of class :c:func:`mps_class_mvt`.

  6. On OS X, signals are no longer used for handling memory protection exceptions. This means that programs are free to handle SIGBUS, but must not install a thread-local Mach exception handler for EXC_BAD_ACCESS exceptions. See :ref:`topic-thread-signal`.

  7. On OS X, when debugging with gdb, you no longer need to turn on dont-handle-bad-access or to request special handling of SIGBUS.

Other changes

  1. On Windows, an execute exception no longer triggers an assertion. See job003301.
  2. Rehashing of large address-based hash tables no longer provokes a nursery collection that immediately renders the hash table stale again. See job003435.
  3. An :ref:`pool-mvt` pool no longer triggers an assertion failure when it runs out of space on its reserved block queue. See job003486.
  4. The -i and -o options no longer cause :program:`mpseventsql` to crash. See job003507.
  5. On Windows, telemetry files now have correct clock values. Previously the top 32 bits were incorrectly output as zero. See job003519.
  6. On 64-bit Windows, it's no longer possible to get a stack overflow exception while the MPS is holding the arena lock. See job003640.

Release 1.111.0

New features

  1. Reporting features have been removed from the :ref:`mpseventcnv <telemetry-mpseventcnv>` utility. Instead, the telemetry system comes with two new utility programs to assist with reporting and analysis: :ref:`mpseventtxt <telemetry-mpseventtxt>` converts an event stream into human-readable form, and :ref:`mpseventsql <telemetry-mpseventsql>` loads an event stream into a SQLite database for further analysis. See :ref:`topic-telemetry`.
  2. The new pool class :ref:`pool-mfs` provides manually managed allocation of fixed-size objects.
  3. The new pool class :ref:`pool-mvt` provides manually managed allocation of variable-size objects using a temporal fit allocation policy (that is, objects that are allocated together are expected to be freed together).

Interface changes

  1. It is no longer necessary for client programs to use :c:func:`mps_tramp` to ensure that exceptions due to barrier hits are caught. This function is now deprecated.
  2. You can set the environment variable :envvar:`MPS_TELEMETRY_CONTROL` to all to make the telemetry system output all events. See :ref:`topic-telemetry`.
  3. New functions :c:func:`mps_telemetry_get`, :c:func:`mps_telemetry_set` and :c:func:`mps_telemetry_reset` provide a more convenient interface to telemetry control than :c:func:`mps_telemetry_control`, which is now deprecated. See :ref:`topic-telemetry`.
  4. The pool classes MV (Manual Variable) and :ref:`pool-snc` are now deprecated.
  5. Allocation frames are now deprecated. See :ref:`topic-frame`.
  6. Additionally, the functions :c:func:`mps_arena_expose`, :c:func:`mps_arena_unsafe_expose_remember_protection`, :c:func:`mps_arena_unsafe_restore_protection`, :c:func:`mps_arena_roots_walk`, and :c:func:`mps_fix` are now deprecated.

Other changes

  1. :c:func:`mps_arena_step` no longer unclamps the arena as a side effect. If the arena is clamped or parked before calling :c:func:`mps_arena_step`, it is clamped afterwards. See job003320.
  2. The ambiguous stack scanner, :c:func:`mps_stack_scan_ambig`, no longer asserts on Linux when there are multiple threads. See job003412.
  3. It is no longer possible for the "ramp" allocation pattern, :c:func:`mps_alloc_pattern_ramp()`, to get stuck. Now :c:func:`mps_ap_alloc_pattern_end` reliably clears this pattern. See job003454.
  4. The build system now correctly detects the FreeBSD operating system running on the x86-64 architecture, for FreeBSD version 9.1 or later. See job003473.

Release 1.110.0

New features

  1. New supported platforms:
    • fri6gc (FreeBSD, x86-64, GCC)
    • lii6gc (Linux, x86-64, GCC)
    • w3i6mv (Windows, x86-64, Microsoft Visual C)
    • xci3ll (OS X, IA-32, Clang/LLVM)
    • xci6gc (OS X, x86-64, GCC)
    • xci6ll (OS X, x86-64, Clang/LLVM)
  2. Support removed for platforms:
    • iam4cc (Irix 6, MIPS R4000, MIPSpro C)
    • lii3eg (Linux, IA-32, EGCS)
    • lippgc (Linux, PowerPC, GCC)
    • o1alcc (OSF/1, Alpha, Digital C)
    • o1algc (OSF/1, Alpha, GCC)
    • s7ppmw (System 7, PowerPC, MetroWerks C)
    • sos8gc (Solaris, SPARC 8, GCC)
    • sos9sc (Solaris, SPARC 9, SunPro C)
    • sus8gc (SunOS, SPARC 8, GCC)
    • xcppgc (OS X, PowerPC, GCC)
  3. On Unix platforms, the MPS can now be built and installed by running ./configure && make install. See :ref:`guide-build`.
  4. The MPS can be compiled in a single step via the new source file mps.c. This also allows you to compile the MPS in the same compilation unit as your object format, allowing the compiler to perform global optimizations between the two. See :ref:`guide-build`.
  5. The set of build varieties has been reduced to three: the :term:`cool` variety for development and debugging, the :term:`hot` variety for production, and the :term:`rash` variety for people who like to live dangerously. See :ref:`topic-error-variety`.
  6. The environment variable :envvar:`MPS_TELEMETRY_CONTROL` can now be set to a space-separated list of event kinds. See :ref:`topic-telemetry`.
  7. Telemetry output is now emitted to the file named by the environment variable :envvar:`MPS_TELEMETRY_FILENAME`, if it is set. See :ref:`topic-telemetry`.

Interface changes

  1. Deprecated constants MPS_MESSAGE_TYPE_FINALIZATION, MPS_MESSAGE_TYPE_GC and MPS_MESSAGE_TYPE_GC_START have been removed. Use :c:func:`mps_message_type_finalization`, :c:func:`mps_message_type_gc` and :c:func:`mps_message_type_gc_start` instead.
  2. Deprecated constants MPS_RANK_AMBIG, MPS_RANK_EXACT and MPS_RANK_WEAK have been removed. Use :c:func:`mps_rank_ambig`, :c:func:`mps_rank_exact` and :c:func:`mps_rank_weak` instead.
  3. Deprecated functions with names starting mps_space_ have been removed. Use the functions with names starting mps_arena_ instead.