Re: SYSV shared memory vs mmap performance

On Fri, Jan 25, 2013 at 05:55:19PM -0500, Robert Haas wrote:
> On Fri, Jan 25, 2013 at 9:38 AM, Francois Tigeot <ftigeot@wolfpond.org> wrote:
> >
> > Some links with more details about improvements and final results:
> > http://www.shiningsilence.com/dbsdlog/2012/09/19/10403.html
> > http://www.shiningsilence.com/dbsdlog/2012/10/11/10544.html
> > http://www.dragonflybsd.org/performance/
> 
> Well, that looks pretty cool.  Is there anything we can sensibly do to
> recover the lost performance on FreeBSD and NetBSD?

Apart from reintroducing SYSV shm usage, I don't think the Postgres team
can do much about it. Mmap really needs kernel work to perform well.

Some FreeBSD people are looking into the issue and have started to run
benchmarks of their own to find out what needs to be fixed; I guess they
will adapt in time.

I'm less optimistic on the NetBSD front: even though I reported major
show-stopper bugs (system died under load and was unable to complete
a pgbench run), no one seemed to care.

-- 
Francois Tigeot