Re: Spinlock performance improvement proposal

OK, testing now with 1000 backends and 2000 buffers.  Will report.

> Bruce Momjian <pgman@candle.pha.pa.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
> 

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