Re: Proposal for enabling auto-vectorization for checksum calculations

Stepan Neretin <slpmcf@gmail.com>

From: Stepan Neretin <slpmcf@gmail.com>

To: Matthew Sterrett <matthewsterrett2@gmail.com>

Cc: pgsql-hackers@lists.postgresql.org, "Devulapalli, Raghuveer" <raghuveer.devulapalli@intel.com>, "Shankaran, Akash" <akash.shankaran@intel.com>

Date: 2025-05-10T11:01:54Z

Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

Use AVX2 for calculating page checksums where available
- 5e13b0f24039 19 (unreleased) landed

Attachments

v2-0001-Enable-autovectorizing-pg_checksum_block.patch (text/x-patch) patch v2-0001
v2-0002-Fix-compilation-on-systems-where-immintrin.h-is-n.patch (text/x-patch) patch v2-0002
v2-0003-Benchmark-code-for-postgres-checksums.patch (text/x-patch) patch v2-0003
v2-0004-fix-bench-compiling.patch (text/x-patch) patch v2-0004

On Sat, May 10, 2025 at 6:01 PM Stepan Neretin <slpmcf@gmail.com> wrote:

>
>
> On Thu, May 8, 2025 at 6:57 AM Matthew Sterrett <
> matthewsterrett2@gmail.com> wrote:
>
>> Hello! I'm still trying to figure out those CI failures, I just wanted
>> to update things.
>>
>> From my testing, with this patch repeatedly disabling/enabling
>> checksums is about 12.4% on an approximately 15 GB database.
>>
>> By the way, I'd love it if anyone could help me figure out how to
>> replicate a CI failure in the Cirrus CI.
>> I haven't been able to figure out how to test CI runs locally, does
>> anyone know a good method to do that?
>>
>>
>>
> Hi Matthew,
>
> Thanks for the patch!
>
> I ran some timing tests:
>
> (without avx2)
>
> Time: 4034.351 ms
> SELECT drive_pg_checksum(512);
>
> (with avx2)
>
>
> Time: 3559.076 ms
> SELECT drive_pg_checksum(512);
>
> Also attached two patches that should fix the CI issues.
>
> Best,
>
> Stepan Neretin
>
>
>
Oops, forgot to attach patches :)

Best,

Stepan Neretin