Is it reliable to increase the MAXCPU in param.h ?

[ProAce]

Testing Report:

Server: HP DL785G5 , AMD Opteron 8356 * 8 ( 32 cores ) , 16G RAM
DB: PostgreSQL 8.3.3 ( install from ports , default option )
Test tool: super-smack ( install from ports )
Disk: 146G SAS * 2 ( RAID 1 on HP P400 )

OS kernel: Just change the 4BSD to ULE , and increase the MAXCPU to 32.
PGSQL's config : default postgresql.conf
super-smack's source: default source file & data

command: repeat 10 super-smack -d pg select-key.smack [# of client] 10000
And I calculate the average of the 10 results for each execution.

# of client  |  query per sec.
====================
01   |   5829
02   |   10663
03   |   14399
04   |   16713
05   |   19662
06   |   22434
07   |   25095
08   |   27464
09   |   29783
10   |   31697
11   |   33514
12   |   35298
13   |   36600
14   |   37721
15   |   38061
16   |   39065
17   |   40350
18   |   40525
19   |   41174
20   |   41721
21   |   41354
22   |   39321
23   |   37905
24   |   31794
25   |   29731
26   |   25782
27   |   26069
28   |   23780
29   |   19475
30   |   17867
31   |   17794
32   |   26065
33   |   35252
34   |   36010
35   |   34396
36   |   33878




2008/7/1, Kris Kennaway <kris at freebsd.org>:
> ProAce wrote:
> > Server: HP DL785G5 with 8 CPU ( 32 cores ) , 16G RAM
> > OS: FreeBSD 7.0-amd64
> > Kernel 1: MAXCPU = 16 ( default )
> > Kernel 2: MAXCPU = 32
> >
> > DL785G5 run with kernel 1 and kernel 2 both successfully, and the
> > FreeBSD can detect the 16 CPUs and 32 CPUs normally ( using top -S
> > command).
> >
> > If I use kernel 2 for postgresql 8.3,  is it reliable and stable?
> >
>
> 32 should be OK, but we haven't had access to such a machine yet (we briefly
> had access to a 16-core system but it melted) so we have not yet tuned for
> performance on it.  FreeBSD 8.0 will run better if you are willing to use a
> development version of FreeBSD.
>
> Kris
>