Ravenbrook · rptb1 · Feb 22, 2023 · Feb 22, 2023 · Feb 22, 2023 · Feb 22, 2023
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+.. mode: -*- rst -*-
+
+===============================
+Memory Pool System Version Plan
+===============================
+
+:tag: plan.mps
+:Author: Gareth Rees
+:Date: 2014-05-16
+:Status: live
+:confidentiality: public
+:copyright: See `C. Copyright and License`_
+:readership: MPS users, MPS project managers, MPS developers
+
+
+1. Introduction
+---------------
+
+This is the version plan [RB-1999-05-20]_ for development of the
+Memory Pool System.
+
+This document will be modified as the project progresses.
+
+
+2. Future versions
+------------------
+
+Version 1.118
+.............
+
+`Migrate the MPS from Perforce to Git <https://github.com/orgs/Ravenbrook/projects/1>`_:
+
+* `GitHub issue #125 <https://github.com/Ravenbrook/mps/issues/125>`_
+  (Version and release procedures use Perforce).  This will be the
+  first version created and managed in Git, and the first release from
+  a Git version.
+
+`Bring Configura forward from version 1.115 <https://github.com/orgs/Ravenbrook/projects/2>`_:
+
+* `GitHub issue #110 <https://github.com/Ravenbrook/mps/issues/110>`_
+  (Ravenbrook MPS sources are out of sync with Configura's sources).
+  This includes a complete assessment of risk to Configura of all
+  changes since 1.115.
+
+* `GitHub issue #111 <https://github.com/Ravenbrook/mps/issues/111>`_
+  (Public MPS source code does not include transforms).
+
+
+3. Past versions
+----------------
+
+Version 1.117
+.............
+
+[The plan for version 1.117 was not recorded in
+//info.ravenbrook.com/project/mps/plan/index.rst#14.  RB 2023-02-22]
+
+
+Version 1.116
+.............
+
+Better measurement and visualization of space and time performance.
+
+Improvements to performance and tunability via separation of concerns
+(see [GDR_2014-05-15]_).
+
+* job003783_ (ChainCondemnAuto condemns too many generations)
+* job003796_ (White segment lookup is slow)
+* job003797_ (AMC space is lost to pinning)
+* job003799_ (Incrementally collecting the nursery may be a waste)
+
+.. _job003783: https://www.ravenbrook.com/project/mps/issue/job003783/
+.. _job003796: https://www.ravenbrook.com/project/mps/issue/job003796/
+.. _job003797: https://www.ravenbrook.com/project/mps/issue/job003797/
+.. _job003799: https://www.ravenbrook.com/project/mps/issue/job003799/
+
+Improvements to flexibility by removing special cases and
+introducing abstractions:
+
+* job003765_ (Pools use GCSeg when they are not GC pools)
+* job003838_ (MVT uses segments unnecessarily)
+
+.. _job003765: https://www.ravenbrook.com/project/mps/issue/job003765/
+.. _job003838: https://www.ravenbrook.com/project/mps/issue/job003838/
+
+Improvements to usability:
+
+* job003794_ (Hard to predict the mortality in a generation)
+
+.. _job003794: https://www.ravenbrook.com/project/mps/issue/job003794/
+
+Improvements to testing:
+
+* job003839_ (No benchmarks for space performance)
+
+.. _job003839: https://www.ravenbrook.com/project/mps/issue/job003839/
+
+
+Version 1.115
+.............
+
+Gain client control over pause times (see [GDR_2014-05-14]_ and [GDR_2014-05-15]_).
+
+* job003539_ (MPS pause times are not well regulated)
+
+.. _job003539: https://www.ravenbrook.com/project/mps/issue/job003539/
+
+
+Version 1.114
+.............
+
+Improvements to performance and tunability via separation of concerns
+(see [GDR_2014-05-15]_).
+
+* job003509_ (MVFF uses segments unnecessarily)
+* job003554_ (MPS slows down considerably when arena is extended)
+* job003701_ (MVSpanAlloc shows up in GC profiles)
+* job003812_ (MVAlloc taking significant CPU in profiles)
+* job003823_ (No control over constant factor in tract management)
+* job003824_ (No control over the constant factor in AMC segment overhead)
+
+.. _job003509: https://www.ravenbrook.com/project/mps/issue/job003509/
+.. _job003554: https://www.ravenbrook.com/project/mps/issue/job003554/
+.. _job003701: https://www.ravenbrook.com/project/mps/issue/job003701/
+.. _job003812: https://www.ravenbrook.com/project/mps/issue/job003812/
+.. _job003823: https://www.ravenbrook.com/project/mps/issue/job003823/
+.. _job003824: https://www.ravenbrook.com/project/mps/issue/job003824/
+
+Improvements to flexibility by removing special cases and
+introducing abstractions:
+
+* job003684_ (Too hard to swap out address range managers)
+* job003685_ (No encapsulation of CBS-failing-over-to-Freelist pattern)
+* job003745_ (AWL alignment is not configurable)
+* job003748_ (Alignment requirements for manual classes are needlessly strict)
+* job003787_ (No systematic interface to size of pools)
+
+.. _job003684: https://www.ravenbrook.com/project/mps/issue/job003684/
+.. _job003685: https://www.ravenbrook.com/project/mps/issue/job003685/
+.. _job003745: https://www.ravenbrook.com/project/mps/issue/job003745/
+.. _job003748: https://www.ravenbrook.com/project/mps/issue/job003748/
+.. _job003787: https://www.ravenbrook.com/project/mps/issue/job003787/
+
+Improvements to robustness:
+
+* job001549_ (Assertion failure ``!AMS_IS_INVALID_COLOUR``)
+* job003359_ (Ambiguous interior pointers do not keep objects alive)
+* job003496_ (Assertion failure in ``mps_arena_roots_walk``)
+* job003751_ (MVFF debug does not work with large objects)
+* job003771_ (AMS with default args never gets collected)
+* job003772_ (AWL doesn't provoke collections)
+* job003773_ (Objects in LO pools are not all finalized)
+
+.. _job001549: https://www.ravenbrook.com/project/mps/issue/job001549/
+.. _job003359: https://www.ravenbrook.com/project/mps/issue/job003359/
+.. _job003496: https://www.ravenbrook.com/project/mps/issue/job003496/
+.. _job003751: https://www.ravenbrook.com/project/mps/issue/job003751/
+.. _job003771: https://www.ravenbrook.com/project/mps/issue/job003771/
+.. _job003772: https://www.ravenbrook.com/project/mps/issue/job003772/
+.. _job003773: https://www.ravenbrook.com/project/mps/issue/job003773/
+
+Improvements to testing:
+
+* job003659_ (Too hard to maintain the test suite)
+* job003716_ ("ANSI" platform is not regularly tested)
+* Static analysis using Coverity_.
+* Test coverage up to 84%.
+
+.. _job003659: https://www.ravenbrook.com/project/mps/issue/job003659/
+.. _job003716: https://www.ravenbrook.com/project/mps/issue/job003716/
+.. _Coverity: http://www.coverity.com/
+
+
+A. References
+-------------
+
+.. [GDR_2014-05-14] "MPS strategic direction proposals"; Gareth Rees;
+   Ravenbrook Limited; 2014-05-14;
+   <https://info.ravenbrook.com/mail/2014/05/14/16-14-34/0/>.
+
+.. [GDR_2014-05-15] "More MPS strategy"; Gareth Rees;
+   Ravenbrook Limited; 2014-05-15;
+   <https://info.ravenbrook.com/mail/2014/05/15/19-19-13/0/>.
+
+.. [RB-1999-05-20] "Product Quality through Change Management";
+   Richard Brooksby; Ravenbrook Limited; 1999-05-20;
+   <https://www.ravenbrook.com/doc/1999/05/20/pqtcm/>.
+
+
+B. Document History
+-------------------
+
+==========  =====  ==================================================
+2023-02-22  RB_    Migrated from Perforce to `MPS public Git repo`_
+==========  =====  ==================================================
+
+.. _RB: mailto:[email protected]
+
+.. _MPS public Git repo: https://github.com/Ravenbrook/mps
+
+
+C. Copyright and License
+------------------------
+
+Copyright © 2013–2023 `Ravenbrook Limited <https://www.ravenbrook.com/>`_.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+1. Redistributions of source code must retain the above copyright
+   notice, this list of conditions and the following disclaimer.
+
+2. Redistributions in binary form must reproduce the above copyright
+   notice, this list of conditions and the following disclaimer in the
+   documentation and/or other materials provided with the distribution.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+
+.. end