Re: [PoC] Improve dead tuple storage for lazy vacuum

Hi,

On 2022-06-28 11:17:42 +0700, John Naylor wrote:
> On Mon, Jun 27, 2022 at 10:23 PM Hannu Krosing <hannuk@google.com> wrote:
> >
> > > Another thought: for non-x86 platforms, the SIMD nodes degenerate to
> > > "simple loop", and looping over up to 32 elements is not great
> > > (although possibly okay). We could do binary search, but that has bad
> > > branch prediction.
> >
> > I am not sure that for relevant non-x86 platforms SIMD / vector
> > instructions would not be used (though it would be a good idea to
> > verify)
> 
> By that logic, we can also dispense with intrinsics on x86 because the
> compiler will autovectorize there too (if I understand your claim
> correctly). I'm not quite convinced of that in this case.

Last time I checked (maybe a year ago?) none of the popular compilers could
autovectorize that code pattern.

Greetings,

Andres Freund