Enable HyperThreading in HP-UX V3

[Md. Minhaz Khan]

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

[vishnu.khandare]

Hi Minhaz,

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

Hope this solves ur query.


Regards
Vishnu Khandare

[Duncan Edmonstone · Accepted solution]

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

[Md. Minhaz Khan]

Thanks everybody.

BR
Minhaz