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diff --git a/libitm/doc/tm-methods-and-method-groups.rst b/libitm/doc/tm-methods-and-method-groups.rst deleted file mode 100644 index a9b56197a5b..00000000000 --- a/libitm/doc/tm-methods-and-method-groups.rst +++ /dev/null @@ -1,47 +0,0 @@ -.. - Copyright 1988-2022 Free Software Foundation, Inc. - This is part of the GCC manual. - For copying conditions, see the copyright.rst file. - -TM methods and method groups -**************************** - -libitm supports several ways of synchronizing transactions with each other. -These TM methods (or TM algorithms) are implemented in the form of -subclasses of ``abi_dispatch``, which provide methods for -transactional loads and stores as well as callbacks for rollback and commit. -All methods that are compatible with each other (i.e., that let concurrently -running transactions still synchronize correctly even if different methods -are used) belong to the same TM method group. Pointers to TM methods can be -obtained using the factory methods prefixed with ``dispatch_`` in -:samp:`libitm_i.h`. There are two special methods, ``dispatch_serial`` and -``dispatch_serialirr``, that are compatible with all methods because they -run transactions completely in serial mode. - -TM method life cycle -^^^^^^^^^^^^^^^^^^^^ - -The state of TM methods does not change after construction, but they do alter -the state of transactions that use this method. However, because -per-transaction data gets used by several methods, ``gtm_thread`` is -responsible for setting an initial state that is useful for all methods. -After that, methods are responsible for resetting/clearing this state on each -rollback or commit (of outermost transactions), so that the transaction -executed next is not affected by the previous transaction. - -There is also global state associated with each method group, which is -initialized and shut down (``method_group::init()`` and ``fini()``) -when switching between method groups (see :samp:`retry.cc`). - -Selecting the default method -^^^^^^^^^^^^^^^^^^^^^^^^^^^^ - -The default method that libitm uses for freshly started transactions (but -not necessarily for restarted transactions) can be set via an environment -variable (:envvar:`ITM_DEFAULT_METHOD`), whose value should be equal to the name -of one of the factory methods returning abi_dispatch subclasses but without -the "dispatch\_" prefix (e.g., "serialirr" instead of -``GTM::dispatch_serialirr()``). - -Note that this environment variable is only a hint for libitm and might not -be supported in the future.
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