Enable HyperThreading in HP-UX V3

Md. Minhaz Khan — Tue, 07 Jun 2011 11:17:17 GMT

Dear HP Engineers,

I have enabled Hyper Threading (HT) in our rx6600 (HP-UX V3) server with below procedure. Please confirm us whether or not it is correct?
If any modification required, please advise:

# setboot -v
....................
....................

Hyperthreading : OFF

# ioscan -fnC processor
Class I H/W Path Driver S/W State H/W Type Description
========================================================================
processor 0 120 processor CLAIMED PROCESSOR Processor
processor 1 121 processor CLAIMED PROCESSOR Processor
processor 2 122 processor CLAIMED PROCESSOR Processor
processor 3 123 processor CLAIMED PROCESSOR Processor

Steps 1:
========

For hp-ux 11iv3, you can enable hyperthreading by two way:

From HP-UX Command line as "root" user

#setboot -m on

or

From EFI Shell

SHELL > cpuconfig threads on

Steps 2:
=======

The kernel tunable "lcpu_attr" will activate use of hyperthreading by the OS.

Now The kernel tunable "lcpu_attr" will need to activate using kctune:

# kctune lcpu_attr=1
==> Update the automatic 'backup' configuration first? y
* The automatic 'backup' configuration has been updated.
* Future operations will update the backup without prompting.
* The requested changes have been applied to the currently
running configuration.
Tunable Value Expression Changes
lcpu_attr (before) 0 Default Imm (auto disabled)
(now) 1 1

# kctune -q lcpu_attr
Tunable Value Expression Changes
lcpu_attr 1 1 Imm (auto disabled)

# ioscan -fnC processor
Class I H/W Path Driver S/W State H/W Type Description
========================================================================
processor 0 120 processor CLAIMED PROCESSOR Processor
processor 1 121 processor CLAIMED PROCESSOR Processor
processor 2 122 processor CLAIMED PROCESSOR Processor
processor 3 123 processor CLAIMED PROCESSOR Processor
processor 4 124 processor CLAIMED PROCESSOR Processor
processor 5 125 processor CLAIMED PROCESSOR Processor
processor 6 126 processor CLAIMED PROCESSOR Processor
processor 7 127 processor CLAIMED PROCESSOR Processor

# setboot -v
....................
....................

Hyperthreading : ON

Thanks
Minhaz

Re: Enable HyperThreading in HP-UX V3

vishnu.khandare — Tue, 07 Jun 2011 11:24:00 GMT

Hi Minhaz,

Its correct procedure to follow for HyperThreading.You can go ahead.

Hope this solves ur query.

Regards
Vishnu Khandare

Re: Enable HyperThreading in HP-UX V3

Duncan Edmonstone — Tue, 07 Jun 2011 11:25:00 GMT

Minhaz,

That all looks correct to me. Whether you get any performance advantage out of doing it though you'll have to see... its not guaranteed by any stretch.

One last point - Hyperthreading is not supported with HP Integrity Virtual Machines - if this system is going to be a HPVM host you'll have to turn hyperthreading off again.

HTH

Duncan

Re: Enable HyperThreading in HP-UX V3

Md. Minhaz Khan — Tue, 07 Jun 2011 12:28:24 GMT

Thanks everybody.

BR
Minhaz

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Enable HyperThreading in HP-UX V3

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Re: Enable HyperThreading in HP-UX V3