Horton

Re: [PATCH] SVE popcount support

Nathan Bossart <nathandbossart@gmail.com>

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From: Nathan Bossart <nathandbossart@gmail.com>
To: John Naylor <johncnaylorls@gmail.com>
Cc: "Chiranmoy.Bhattacharya@fujitsu.com" <Chiranmoy.Bhattacharya@fujitsu.com>, "Malladi, Rama" <ramamalladi@hotmail.com>, pgsql-hackers <pgsql-hackers@postgresql.org>, "Ragesh.Hajela@fujitsu.com" <Ragesh.Hajela@fujitsu.com>, Salvatore Dipietro <dipiets@amazon.com>, "Devanga.Susmitha@fujitsu.com" <Devanga.Susmitha@fujitsu.com>
Date: 2025-03-28T21:22:17Z
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 →

  1. Optimize popcount functions with ARM SVE intrinsics.

  2. Optimize popcount functions with ARM Neon intrinsics.

  3. Rename TRY_POPCNT_FAST to TRY_POPCNT_X86_64.

Committed.

On Fri, Mar 28, 2025 at 10:25:26AM -0500, Nathan Bossart wrote:
> On Thu, Mar 27, 2025 at 03:31:27PM +0700, John Naylor wrote:
>> On Thu, Mar 27, 2025 at 10:38 AM Nathan Bossart
>> <nathandbossart@gmail.com> wrote:
>>> I also noticed a silly mistake in 0003 that would cause us to potentially
>>> skip part of the tail.  That should be fixed now.
>> 
>> I'm not sure whether that meant it could return the wrong answer, or
>> just make more work for paths further down.
>> If the former, then our test coverage is not adequate.
> 
> This one is my bad.  I think the issue is that I'm writing this stuff on a
> machine that doesn't have SVE, so obviously my tests are happy as long as
> the Neon stuff is okay.  We do have some tests in bit.sql that should in
> theory find this stuff.  I'll be sure to verify all of this on a machine
> with SVE...

I verified that the tests failed without this fix on a machine with SVE.

-- 
nathan