Re: define pg_structiszero(addr, s, r)
От | Bertrand Drouvot |
---|---|
Тема | Re: define pg_structiszero(addr, s, r) |
Дата | |
Msg-id | Zyozu5B6+W8FyF8m@ip-10-97-1-34.eu-west-3.compute.internal обсуждение исходный текст |
Ответ на | Re: define pg_structiszero(addr, s, r) (David Rowley <dgrowleyml@gmail.com>) |
Ответы |
Re: define pg_structiszero(addr, s, r)
Re: define pg_structiszero(addr, s, r) |
Список | pgsql-hackers |
Hi, On Tue, Nov 05, 2024 at 05:08:41PM +1300, David Rowley wrote: > On Tue, 5 Nov 2024 at 06:39, Ranier Vilela <ranier.vf@gmail.com> wrote: > > I think we can add a small optimization to this last patch [1]. > > I think if you want to make it faster, you could partially unroll the > inner-most loop, like: > > // size_t * 4 > for (; p < aligned_end - (sizeof(size_t) * 3); p += sizeof(size_t) * 4) > { > if (((size_t *) p)[0] != 0 | ((size_t *) p)[1] != 0 | ((size_t *) > p)[2] != 0 | ((size_t *) p)[3] != 0) > return false; > } Another option could be to use SIMD instructions to check multiple bytes is zero in a single operation. Maybe just an idea to keep in mind and experiment if we feel the need later on. Regards, -- Bertrand Drouvot PostgreSQL Contributors Team RDS Open Source Databases Amazon Web Services: https://aws.amazon.com
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