Re: postgres 9.3 vs. 9.4

With pg_test_timing I can see, that overhead is 48 nsec on my server and 32 nsec on the laptop.
what makes this difference and have it any influence on the overall performance?

Tigran.

----- Original Message -----
> From: "Mark Kirkwood" <mark.kirkwood@catalyst.net.nz>
> To: "Tigran Mkrtchyan" <tigran.mkrtchyan@desy.de>, "Merlin Moncure" <mmoncure@gmail.com>
> Cc: "postgres performance list" <pgsql-performance@postgresql.org>
> Sent: Wednesday, September 24, 2014 12:04:12 PM
> Subject: Re: [PERFORM] postgres 9.3 vs. 9.4
>
> On 24/09/14 21:23, Mkrtchyan, Tigran wrote:
> > Hi Merlin et al.
> >
> > after building postgres 9.4 myself from sources I get the same performance
> > as
> > with 9.3. The difference was in the value of debug_assertions setting.
> >
> > Now the next step. Why my 3 years old laptop gets x1.8 times more tps than
> > my one month old server?
> > And Mark Kirkwood's desktop gets x2 times more tps as well? Is there some
> > special optimization
> > for i7 which does not work with Intel(R) Xeon(R) CPU E5-2660?
> >
> >
>
> Yes - firstly, nicely done re finding the assertions (my 9.4 beta2 was
> built from src - never thought to mention sorry)!
>
> I'd guess that you are seeing some bios setting re the p320 SSD - it
> *should* be seriously fast...but does not seem to be. You could try
> running some pure IO benchmarks to confirm this (e.g fio). Also see if
> the manual for however it is attached to the system allows for some
> optimized-for-ssd settings that tend to work better (altho these usually
> imply the drive is plugged into an adapter card of some kind - mind you
> your p320 *does* used a custom connector that does 2.5" SATA to PCIe
> style interconnect so I'd look to debug that first).
>
> Cheers
>
> Mark
>
>