Re: Improving spin-lock implementation on ARM.

On Tue, Dec 1, 2020 at 6:19 PM Krunal Bauskar <krunalbauskar@gmail.com> wrote:
> I would request you guys to re-think it from this perspective to help ensure that PGSQL can scale well on ARM.
> s_lock becomes a top-most function and LSE is not a universal solution but CAS surely helps ease the main
bottleneck.

CAS patch isn't proven to be a universal solution as well.  We have
tested the patch on just a few processors, and Tom has seen the
regression [1].  The benchmark used by Tom was artificial, but the
results may be relevant for some real-life workload.

I'm expressing just my personal opinion, other committers can have
different opinions.  I don't particularly think this topic is
necessarily a non-starter.  But I do think that given ambiguity we've
observed in the benchmark, much more research is needed to push this
topic forward.

Links.
1. https://www.postgresql.org/message-id/741389.1606530957%40sss.pgh.pa.us

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Regards,
Alexander Korotkov