Re: Improve CRC32C performance on SSE4.2

John Naylor <johncnaylorls@gmail.com>

From: John Naylor <johncnaylorls@gmail.com>

To: "Devulapalli, Raghuveer" <raghuveer.devulapalli@intel.com>

Cc: Nathan Bossart <nathandbossart@gmail.com>, "pgsql-hackers@lists.postgresql.org" <pgsql-hackers@lists.postgresql.org>, "Shankaran, Akash" <akash.shankaran@intel.com>

Date: 2025-03-12T06:54:02Z

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 →

Include _mm512_zextsi128_si512() in AVX-512 configure probes.
- ccd5bc93fdfe 18.0 landed
Properly fix AVX-512 CRC calculation bug
- 43da394304fb 18.0 landed
Workaround code generation bug in clang
- f83f14881c7a 18.0 landed
Compute CRC32C using AVX-512 instructions where available
- 3c6e8c123896 18.0 landed
Inline CRC computation for small fixed-length input on x86
- e2809e3a1015 18.0 landed
Be more paranoid in configure's checks for CRC and POPCNT intrinsics.
- fdb5dd6331e3 18.0 cited

On Wed, Mar 12, 2025 at 3:57 AM Devulapalli, Raghuveer
<raghuveer.devulapalli@intel.com> wrote:
>
> > I've gone ahead and added the generated AVX-512 algorithm in v14-0005

> I'm a little confused. Why is v14 missing the earlier versions of pclmul implementation that works without avx-512?

As I mentioned upthread, the 128-bit implementation regresses on Zen 2
up to at least 256 bytes.

--
John Naylor
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