bcb2cf41f9
This adds additional x86 specific CPUID checks for flags needed for determining whether the Time-Stamp Counter (TSC) is usable on a given system, as well as a helper function to retrieve the TSC frequency from CPUID. This is intended for a future patch that will utilize the TSC to lower the overhead of timing instrumentation. In passing, always make pg_cpuid_subleaf reset the variables used for its result, to avoid accidentally using stale results if __get_cpuid_count errors out and the caller doesn't check for it. Author: Lukas Fittl <lukas@fittl.com> Author: David Geier <geidav.pg@gmail.com> Author: Andres Freund <andres@anarazel.de> Reviewed-by: Andres Freund <andres@anarazel.de> Reviewed-by: David Geier <geidav.pg@gmail.com> Reviewed-by: John Naylor <john.naylor@postgresql.org> Reviewed-by: Jakub Wartak <jakub.wartak@enterprisedb.com> (in an earlier version) Discussion: https://www.postgresql.org/message-id/flat/20200612232810.f46nbqkdhbutzqdg%40alap3.anarazel.de
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.
Copyright and license information can be found in the file COPYRIGHT.
General documentation about this version of PostgreSQL can be found at https://www.postgresql.org/docs/devel/. In particular, information about building PostgreSQL from the source code can be found at https://www.postgresql.org/docs/devel/installation.html.
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/.