Re: Seeing context switch storm with 10/13 snapshot of

Simon Riggs <simon@2ndquadrant.com> writes:
> It would be good right now to have a multi-process test harness that
> would allow us to test out different spin lock code without the rest of
> PostgreSQL getting in the way of testing. If we can isolate the issue
> outside of PostgreSQL it will be much easier to fix.

Actually I disagree with that, on three grounds:

1. Optimizing for an artificial environment may result in the wrong
optimization.

2. I don't think you'll be able to prove anything except that all SMP
designs ultimately suck.  There is no hardware on the planet that can
trade cache lines back and forth at instruction-dispatch rates.

3. The problem right now is not lack of ability to reproduce the
problem, it is lack of ideas how to fix it.  Building an artificial
testbed is just directing effort into make-work rather than towards
solving the problem.
        regards, tom lane