Horton

Re: Optimize numeric multiplication for one and two base-NBASE digit multiplicands.

Joel Jacobson <joel@compiler.org>

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From: "Joel Jacobson" <joel@compiler.org>
To: "Dean Rasheed" <dean.a.rasheed@gmail.com>
Cc: Dagfinn Ilmari Mannsåker <ilmari@ilmari.org>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2024-07-04T10:38:59Z
Lists: pgsql-hackers 
On Thu, Jul 4, 2024, at 09:38, Joel Jacobson wrote:
> Summary of benchmark results:
>
>          cpu          | var1ndigits |                           winner
> ----------------------+-------------+-------------------------------------------------------------
..
> v5-optimize-numeric-mul_var-small-var1-arbitrary-var2.patch
>  AMD Ryzen 9 7950X3D  |           3 | 
> v5-optimize-numeric-mul_var-small-var1-arbitrary-var2.patch
...
>  Apple M3 Max         |           3 | 
> v5-optimize-numeric-mul_var-small-var1-arbitrary-var2.patch
...
>  Intel Core i9-14900K |           3 | 
> v5-optimize-numeric-mul_var-small-var1-arbitrary-var2.patch

Since v5-add-mul_var_int.patch only implements (var1ndigits <= 2)
it can't possibly win the var1ndigits=3 competition.

/Joel

Commits

  1. Optimise numeric multiplication for short inputs.

  2. Optimise numeric division for 3 and 4 base-NBASE digit divisors.

  3. Optimise numeric division for one and two base-NBASE digit divisors.