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We already rely on autovectorization for computing page checksums, but on x86 we can get a further several-fold performance increase by annotating pg_checksum_block() with a function target attribute for the AVX2 instruction set extension. Not only does that use 256-bit registers, it can also use vector multiplication rather than the vector shifts and adds used in SSE2. Similar to other hardware-specific paths, we set a function pointer on first use. We don't bother to avoid this on platforms without AVX2 since the overhead of indirect calls doesn't matter for multi-kilobyte inputs. However, we do arrange so that only core has the function pointer mechanism. External programs will continue to build a normal static function and don't need to be aware of this. This matters most when using io_uring since in that case the checksum computation is not done in parallel by IO workers. Co-authored-by: Matthew Sterrett <matthewsterrett2@gmail.com> Co-authored-by: Andrew Kim <andrew.kim@intel.com> Reviewed-by: Oleg Tselebrovskiy <o.tselebrovskiy@postgrespro.ru> Tested-by: Ants Aasma <ants.aasma@cybertec.at> Tested-by: Stepan Neretin <slpmcf@gmail.com> (earlier version) Discussion: https://postgr.es/m/CA+vA85_5GTu+HHniSbvvP+8k3=xZO=WE84NPwiKyxztqvpfZ3Q@mail.gmail.com Discussion: https://postgr.es/m/20250911054220.3784-1-root%40ip-172-31-36-228.ec2.internal |
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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/.