Dave McGuire <mcguire@neurotica.com> writes:
> On 06/29/2014 10:54 AM, Andres Freund wrote:
>> Maybe I'm just not playful enough, but keeping a platform alive so we
>> can run postgres in simulator seems a bit, well, pointless.
> On the "in a simulator" matter: It's important to keep in mind that
> there are more VAXen out there than just simulated ones. I'm offering
> up a simulated one here because I can spin it up in a dedicated VM on a
> VMware host that's already running and I already have power budget for.
> I could just as easily run it on real hardware...there are, at last
> count, close to forty real-iron VAXen here, but only a few of those are
> running 24/7. I'd happily bring up another one to do Postgres builds
> and testing, if someone will send me the bucks to pay for the additional
> power and cooling. (that is a real offer)
Well, the issue from our point of view is that a lot of what we care about
testing is extremely low-level hardware behavior, like whether spinlocks
work as expected across processors. It's not clear that a simulator would
provide a sufficiently accurate emulation.
OTOH, the really nasty issues like cache coherency rules don't arise in
single-processor systems. So unless you have a multiprocessor VAX
available to spin up, a simulator may tell us as much as we'd learn
anyway.
(If you have got one, maybe some cash could be found --- we do have
project funds available, and I think they'd be well spent on testing
purposes. I don't make those decisions though.)
regards, tom lane
