Re: avoid some calls to memset with array initializer

From: rmrodriguez(at)carto(dot)com
To: Justin Pryzby <pryzby(at)telsasoft(dot)com>
Cc: PostgreSQL mailing lists <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: avoid some calls to memset with array initializer
Date: 2020-01-02 17:18:54
Message-ID: CAM6_UM6OfZCECoqSFEf6=oN-=sLAU5CGTBOM3seL0h2FOicQpg@mail.gmail.com
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I think this proposal is the same as [1], so you might want to read that thread.

1- https://www.postgresql.org/message-id/flat/201DD0641B056142AC8C6645EC1B5F62014B919631%40SYD1217

On Thu, Jan 2, 2020 at 5:38 PM Justin Pryzby <pryzby(at)telsasoft(dot)com> wrote:
>
> Is there any appetite for use of array initializer rather than memset, as in
> attached ? So far, I only looked for "memset.*null", and I can't see that any
> of these are hot paths, but saves a cycle or two and a line of code for each.
>
> gcc 4.9.2 with -O2 emits smaller code with array initializer than with inlined
> call to memset.
>
> $ wc -l contrib/pageinspect/heapfuncs.S?
> 22159 contrib/pageinspect/heapfuncs.S0
> 22011 contrib/pageinspect/heapfuncs.S1
>
> Also true of gcc 5.4. And 7.3:
>
> 25294 contrib/pageinspect/heapfuncs.S0
> 25234 contrib/pageinspect/heapfuncs.S1

--
Raúl Marín Rodríguez
carto.com

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