| From: | Thomas Munro <thomas(dot)munro(at)enterprisedb(dot)com> |
|---|---|
| To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
| Cc: | Heikki Linnakangas <hlinnaka(at)iki(dot)fi>, Andres Freund <andres(at)anarazel(dot)de>, Yuqi Gu <Yuqi(dot)Gu(at)arm(dot)com>, "pgsql-hackers(at)postgresql(dot)org" <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: Optimize Arm64 crc32c implementation in Postgresql |
| Date: | 2018-05-02 21:47:38 |
| Message-ID: | CAEepm=0V6o6J+C2S3=Ev42SQUri-bnYvs9r+y1dBsaBenrripA@mail.gmail.com |
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| Lists: | pgsql-hackers |
On Thu, May 3, 2018 at 2:30 AM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> Do you really need the pg_crc32c_armv8_choose_dummy global variable?
> That seems pretty ugly. If you're concerned about the compiler
> optimizing away the call to the crc function, you could write it like
>
> result = (pg_comp_crc32c_armv8(0, 0, 0) == expected-value);
>
> which'd provide a bit of extra checking that the code's not broken,
> too.
True. Of course I needed an interesting length too...
--
Thomas Munro
http://www.enterprisedb.com
| Attachment | Content-Type | Size |
|---|---|---|
| 0001-Use-a-portable-way-to-detect-ARMv8-CRC32-hardware-v2.patch | application/octet-stream | 5.6 KB |
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