Re: Spinlock performance improvement proposal

Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us> writes:
> No scale factor, as I illustrated from the initialization command I
> used. Standard buffers too. Let me know what values I should use for
> testing.

Scale factor has to be >= max number of clients you use, else you're
just measuring serialization on the "branch" rows.

I think the default NBuffers (64) is too low to give meaningful
performance numbers, too. I've been thinking that maybe we should
raise it to 1000 or so by default. This would trigger startup failures
on platforms with small SHMMAX, but we could tell people to use -B until
they get around to fixing their kernel settings. It's been a long time
since we fit into a 1-MB shared memory segment at the default settings
anyway, so maybe it's time to select somewhat-realistic defaults.
What we have now is neither very useful nor the lowest common
denominator...

regards, tom lane