Re: speed up verifying UTF-8

John Naylor <john.naylor@enterprisedb.com>

From: John Naylor <john.naylor@enterprisedb.com>

To: Vladimir Sitnikov <sitnikov.vladimir@gmail.com>

Cc: pgsql-hackers <pgsql-hackers@postgresql.org>, Amit Khandekar <amitdkhan.pg@gmail.com>, Heikki Linnakangas <hlinnaka@iki.fi>, Thomas Munro <thomas.munro@gmail.com>, Greg Stark <stark@mit.edu>

Date: 2021-08-04T11:22:57Z

Lists: pgsql-hackers

Attachments

v22-0001-Add-fast-paths-for-validating-UTF-8-text.patch (application/octet-stream) patch v22-0001

I wrote:
> If we have only 16 bytes in the input, it still seems to be faster to use
SSE, even though it's called through a function pointer on x86. I didn't
test the DFA path, but I don't think the conclusion would be different.
I'll include the 16 threshold next time I need to update the patch.

v22 attached, which changes the threshold to 16, with a few other cosmetic
adjustments, mostly in the comments.

--
John Naylor
EDB: http://www.enterprisedb.com

Commits

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

Simplify coding style of is_valid_ascii()
- 6b41a1579bd3 16.0 landed
Apply auto-vectorization to the inner loop of numeric multiplication.
- 88709176236c 14.0 cited