Re: removing old ports and architectures

On 2013-10-12 18:35:00 -0700, Peter Geoghegan wrote:
> Not so sure about these.
> > - M32R (no userspace CAS afaics)

I don't think M32R will hurt us/anybody much.

> > - 32bit/<v9 sparc (doesn't have proper atomics, old)

Sparc v9 is from 1995, so I think not supporting it anymore is
fair. It's afaics not supported by sun studio's intrics either.

> > - mips for anything but gcc > 4.4, using gcc's atomics support

The reason I'd like to de-support mips for older GCCs is that writing
assembler for them isn't trivial enough to do it blindly and I've had -
for other stuff - difficulties getting my hand on them. GCC provides all
the atomics for mips since 4.2, so we can just rely on that.

> > - s390 for anything but gcc > 4.4, using gcc's atomics support

Easier to write assembler, but still untestable and even harder to get
access on.
I think 4.2 should be fine as well.

> I think we should think hard about removing support for MIPS. A lot of
> Chinese chip manufacturers have licensed MIPS technology in just the
> last couple of years, so there is plenty of it out there; I'd be
> slightly concerned that the proposed restrictions on MIPS would be
> onerous. Much of this is the kind of hardware that a person might
> plausibly want to run Postgres on.

That's a fair point. But all of them will use gcc, right? I've
previously thought we'd need 4.4 because there's an incompatibility
between 4.3 and 4.4 but I think it won't touch us, so 4.2 which added
atomics for mips seems fine. Given there's no buildfarm animal and
there's lots of variety out there that seems like a fair amount of
support.

Greetings,

Andres Freund

--
Andres Freund http://www.2ndQuadrant.com/
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