Re: pgbench - add pseudo-random permutation function

Fabien COELHO <coelho@cri.ensmp.fr>

From: Fabien COELHO <coelho@cri.ensmp.fr>

To: Michael Paquier <michael@paquier.xyz>

Cc: Thomas Munro <thomas.munro@enterprisedb.com>, hironobu@interdb.jp, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>

Date: 2018-10-01T11:19:42Z

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 →

pgbench: Function to generate random permutations.
- 6b258e3d688d 14.0 landed
Add basic support for using the POPCNT and SSE4.2s LZCNT opcodes
- 711bab1e4d19 12.0 cited
Further improve code for probing the availability of ARM CRC instructions.
- a7a7387575b8 11.0 cited

Attachments

pgbench-prp-func-6.patch (text/x-diff) patch

>     PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
> Subject: Re: pgbench - add pseudo-random permutation function
> 
> On Wed, Sep 26, 2018 at 01:20:49PM +0200, Fabien COELHO wrote:
>> So, am I right to deducing that you are satisfied with the current status of
>> the patch, with the nbits implementation either based on popcount (v4) or
>> clz (v5) compiler intrinsics? I think that the clz option is better.
>
> Fabien, please note that v5 does not apply,

Indeed, tests interact with 92a0342 committed on Thursday.

Here is a rebase of the latest version based on CLZ. According to basic 
test I made, the underlying hardware instruction seems to be more often 
available.

> so I moved this patch to next CF, waiting on author.

I'm going to change its state to "Needs review".

-- 
Fabien.