Re: [HACKERS] LWLock optimization for multicore Power machines

Am Dienstag, den 07.02.2017, 16:48 +0300 schrieb Alexander Korotkov:
> But win isn't
> as high as I observed earlier.  And I wonder why absolute numbers are
> lower
> than in our earlier experiments.  We used IBM E880 which is actually
> two

Did you run your tests on bare metal or were they also virtualized?

> nodes with interconnect.  However interconnect is not fast enough to
> make
> one PostgreSQL instance work on both nodes.  Thus, used half of IBM
> E880
> which has 4 sockets and 32 physical cores.  While you use IBM E850
> which is
> really single node with 4 sockets and 48 physical cores.  Thus, it
> seems
> that you have lower absolute numbers on more powerful hardware.  That
> makes
> me uneasy and I think we probably don't get the best from this
> hardware.
> Just in case, do you use SMT=8?

Yes, SMT=8 was used.

The machine has 4 sockets, 8 Core each, 3.7 GHz clock frequency. The
Ubuntu LPAR running on PowerVM isn't using all physical cores,
currently 28 cores are assigned (=224 SMT Threads). The other cores are
dedicated to the PowerVM hypervisor and a (very) small AIX LPAR.