Re: define pg_structiszero(addr, s, r) - Mailing list pgsql-hackers

From David Rowley
Subject Re: define pg_structiszero(addr, s, r)
Date
Msg-id CAApHDvq=udkVyRBTvU+K6Ov4VTOzDQpG8=081-8+bNQTTTHxFQ@mail.gmail.com
Whole thread Raw
In response to Re: define pg_structiszero(addr, s, r)  (Peter Eisentraut <peter@eisentraut.org>)
List pgsql-hackers
On Fri, 1 Nov 2024 at 20:14, Michael Paquier <michael@paquier.xyz> wrote:
> 2) On HEAD at 49d6c7d8daba:
> .LVL299:
>    .loc 1 131 16 is_stmt 0 discriminator 1 view .LVU524
>    cmpq    $8192, %rbx
>    je      .L419
>
> 3) With the patch sent at [1]:
> .LVL306:
>    .loc 3 201 23 is_stmt 1 discriminator 1 view .LVU545
>    cmpq    $8192, %rbx
>    jne     .L417
>
> So it does not matter one way or another for 2) or 3), does it?

The patch in [1] will fix the bug. But I'm still concerned about the
performance implications of moving to byte-at-a-time processing. There
are about 8 times more instructions being expected to do the same
work.

David

> [1]: https://www.postgresql.org/message-id/ZyR02ofHiWG1HmLI@paquier.xyz



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