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Presently, all platforms implement atomic exchanges by performing an atomic compare-and-swap in a loop until it succeeds. This can be especially expensive when there is contention on the atomic variable. This commit optimizes atomic exchanges on many platforms by using compiler intrinsics, which should compile into something much less expensive than a compare-and-swap loop. Since these intrinsics have been available for some time, the inline assembly implementations are omitted. Suggested-by: Andres Freund Reviewed-by: Andres Freund Discussion: https://postgr.es/m/20231129212905.GA1258737%40nathanxps13
PostgreSQL Database Management System ===================================== This directory contains the source code distribution of the PostgreSQL database management system. PostgreSQL is an advanced object-relational database management system that supports an extended subset of the SQL standard, including transactions, foreign keys, subqueries, triggers, user-defined types and functions. This distribution also contains C language bindings. See the file INSTALL for instructions on how to build and install PostgreSQL. That file also lists supported operating systems and hardware platforms and contains information regarding any other software packages that are required to build or run the PostgreSQL system. Copyright and license information can be found in the file COPYRIGHT. A comprehensive documentation set is included in this distribution; it can be read as described in the installation instructions. The latest version of this software, and related software, may be obtained at https://www.postgresql.org/download/. For more information look at our web site located at https://www.postgresql.org/.