Re: Sybase on UltraSPARC IV

From: Anthony Mandic (am_at_*t.com.au)
Date: 09/29/04 

Date: Wed, 29 Sep 2004 11:25:14 +1000

Per Eirik wrote:
>
> Suns new UltraSPARC IV processor supports Chip Multi-Threading (CMT) where
> each physical CPU act as two logical CPUs to the OS:
>
> http://www.sun.com/servers/highend/whitepapers/Sun_Fire_Enterprise_Servers_Performance.pdf
>
> I have heard that Sybase UK claims that you have to buy two Internet Access
> Licences for each UltraSPARC IV CPU because it acts as two CPUs to the OS.
> Can this really be true?

        I very much doubt it. Its best to ask your local Sybase sales rep.
        But, if its one physical CPU, I don't see how they can charge you
        a license for two (assuming your licensing is CPU based). Regardless,
        an Internet Access license isn't dependant on the number of CPUs
        (or is it?). The real issue would be - how many Sybase ASE engines
        can you run? If its only one, then its only the one CPU to ASE.

> In case, is it possible to turn off Chip Multi-Threading on Sun/Solaris
> servers?

        No idea. Its best to ask that in the Solaris or Sun hardware newsgroup.
        Sun will have info online as well.

> I think CMT is comparable to Hyperthreading on Intel XEON CPUs. Sybase
> recommends that Hyperthreading should be turned off to maximize Sybase
> performance on Linux, see page 3:
>
> http://www.sybase.com/content/1025313/linux_optimizing_performance_wp.pdf
>
> Would that also be the case for UltraSPARC IV processors?

        Hard to say. Sybase ASE has its own threading model so it doesn't
        make use of an OS's own threading. Whether its on or off makes no
        difference to ASE.

-am © 2004