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Redhat Linux AS 3 U7 can't detect 16 logical CPUs on DL760G2

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richeal75
Advisor

Redhat Linux AS 3 U7 can't detect 16 logical CPUs on DL760G2

HW: DL760G2 with 8 physical CPUs , qty=2
SW: Redhat Linux AS3 U7

problem: Linux only can detect 8 CPUs after enabled Hyperthreading in RBSU.

customer has two DL760G2 servers , each server has same configuration (8 physical CPUS), and install same OS version:redhat linux AS3 U7 , but it very strange that Redhat Linux can detect 16 logical cpus on one server A , but only can detect 8 logical cpus on other serverB.

Move OS of Server A to server B , but serverA's OS still only can detect 8 logical cpus on Server B.

what 's the root cause ?

zhangyi
6 REPLIES
Ivan Ferreira
Honored Contributor

Re: Redhat Linux AS 3 U7 can't detect 16 logical CPUs on DL760G2

Maybe the kernel was booted with the noht option. The the kernel boot options.
Por que hacerlo dificil si es posible hacerlo facil? - Why do it the hard way, when you can do it the easy way?
Steven E. Protter
Exalted Contributor

Re: Redhat Linux AS 3 U7 can't detect 16 logical CPUs on DL760G2

Shalom,

As a precaution make sure the systems firmware and such is up to date with the DL780 cd/dvd that is bootable and ships with the system.

Make sure you boot the system with a kernel, smp or hugement that supports multiple processors.

You may need to patch the system up to Update 8, there could be a bug or problem with the kernel.

SEP
Steven E Protter
Owner of ISN Corporation
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Ivan Ferreira
Honored Contributor
Solution

Re: Redhat Linux AS 3 U7 can't detect 16 logical CPUs on DL760G2

Now that you methion it, check if the operating system selection in the BIOS is correct.
Por que hacerlo dificil si es posible hacerlo facil? - Why do it the hard way, when you can do it the easy way?
richeal75
Advisor

Re: Redhat Linux AS 3 U7 can't detect 16 logical CPUs on DL760G2

Dear ALL,

Problem resovled after changed OS selection to Linux in RBSU.

thanks for your help.

zhangyi.
richeal75
Advisor

Re: Redhat Linux AS 3 U7 can't detect 16 logical CPUs on DL760G2

another thing : is there any document related the issue ? and customer need it.
Ivan Ferreira
Honored Contributor

Re: Redhat Linux AS 3 U7 can't detect 16 logical CPUs on DL760G2

This is a document that may help you. It describes the problem, it's a Microsoft document, but the same rules apply.

http://support.microsoft.com/?scid=kb%3Ben-us%3B252326&x=11&y=12
Por que hacerlo dificil si es posible hacerlo facil? - Why do it the hard way, when you can do it the easy way?