PostgreSQL performance on FreeBSD

Konstantin Belousov kostikbel at
Fri Jun 3 17:26:44 UTC 2016

On Fri, Jun 03, 2016 at 09:29:16AM -0600, Alan Somers wrote:
> I notice that, with the exception of the VM_PHYSSEG_MAX change, these
> patches never made it into head or ports.  Are they unsuitable for low
> core-count machines, or is there some other reason not to commit them?
>  If not, what would it take to get these into 11.0 or 11.1 ?

The fast page fault handler was redesigned and committed in r269728
and r270011 (with several follow-ups).
Instead of lock-less buffer queues iterators, Jeff changed buffer allocator
to use uma, see r289279.  Other improvement to the buffer cache was
committed as r267255.

What was not committed is the aggressive pre-population of the phys objects
mem queue, and a knob to further split NUMA domains into smaller domains.
The later change is rotten.

In fact, I think that with that load, what you would see right now on
HEAD, is the contention on vm_page_queue_free_mtx.  There are plans to
handle it.

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