hyperthreading

[brian_31]

Could someone please let me know how to Disable hyperthreading in redhat AS3?

Thanks

Brian

[Ivan Ferreira]

Normally, you disable hyperthreading in the computer bios, not in the Operatin System.

[Ryan Goh]

You have two way to disable hyperthreading, either disable Hyper-Threading in the kernel or sisable Hyper-threading in system BIOS. You can disable Hyper-Threading in the kernel by specify the noht switch in the kernel line of the grub configuration file.

[George Liu_4]

You may disable HT in BIOS.
But if you have only one processor, you may use non-smp kernel to get the same result.

[Steven E. Protter]

Shalom Brian,

Hyperthreading is disabled in the computer bios. I noticed Red Hat did this in their labs for the RHCE examination.

It may result in a performance hit.

SEP

[Mike Stroyan]

A. Having hyperthreading disabled may result in a performance hit.
B. Having hyperthreading enabled may result in a performance hit.
C. All of the above.

I pick "C". It depends. But I would default to disabling it.

[Alexander Finkel]

Brian,

Ryan Goh is correct. Here is an example entry in grub.conf from one of my servers that has HyperThreading disabled via Kernel option:

title Red Hat Enterprise Linux ES (2.4.21-37.ELsmp)
root (hd0,0)
kernel /vmlinuz-2.4.21-37.ELsmp ro noht root=LABEL=/
initrd /initrd-2.4.21-37.ELsmp.img