Re: How to activate a hyperthreading processor

On Oct 18, 8:08 am, "Marc F. Neininger"
<doesnt.ex..._at_champagnierle.de> wrote:
> fitzjarr..._at_cox.net schrieb:
>
>
>
>
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> > On Oct 18, 9:10 am, "Marc F. Neininger"
> > <doesnt.ex..._at_champagnierle.de> wrote:
> >> hpuxrac schrieb:
>
> >>> On Oct 18, 8:50 am, "Marc F. Neininger"
> >>> <doesnt.ex..._at_champagnierle.de> wrote:
> >>>> Hello,
> >>>> Is the number of CPUs determined and configured at boot time or at
> >>>> installation time?
> >>>> I installed 10g EE on a Debian Linux system. During installation the
> >>>> distro kernel was not capable of hyperthreading but worked.
> >>>> Now I changed the kernel to a custom built one which uses HT. My scripts
> >>>> do use both CPUS, the DBMS doesn't. The DMBS just switches from one to
> >>>> the second virtual CPU.
> >>>> TIA
> >>>> Marc
> >>> Did you try re-linking?
> >> ??? Sorry, what do you mean by that? Reinstallation of the software?
>
> >> Greets
>
> >> Marc- Hide quoted text -
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> >> - Show quoted text -
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> > No, you connect to the server using the 'oracle' account , set the
> > proper ORACLE_HOME and other associated environment variables and
> > type:
>
> > relink all
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> > at the shell prompt.
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> > David Fitzjarrell
>
> Hi David,
>
> thanks for the advice. Unfortunately it didn't work. Relink worked,
> showed trillions of lines, DBMS worked as fine afterwards as before, but
> the load is still not balanced between the CPUs.
>
> Thanks
>
> Marc

I could be out of date here, but it is my understanding that Oracle simply asks the O/S how many processors there are and sets cpu_count accordingly, with nothing special for hyperthreading. If there are any issues, you are supposed to ask Oracle support. That presupposes you are using a supported configuration, and have support, of course.

There doesn't need to be anything special, since current Oracle versions can simply decide if processors are "fast" or "slow."

You may also be working under some misapprehension about load balancing.

See http://asktom.oracle.com/pls/asktom/f?p=100:11:0::::P11_QUESTION_ID:36798353051561 especially the post entitled "Hyperthreads Myths"

jg

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