only one logical CPU used in Xeon

John Baldwin jhb at
Thu Mar 12 06:58:45 PDT 2009

On Wednesday 11 March 2009 11:01:51 am Oliver Fromme wrote:
> Here's how you can see the details in the demsg output:
> The older machine:
>  > Features = 0xbfebfbff <...,HTT,...>
> The "HTT" bit in the features bitmask indicates that the
> processor supports hyperthreading.

No, that flag just means it supports a register where you can ask for the 
total number of threads/cores per package.  Multi-core CPUs that don't have 
hyperthreads have 'HTT' set, but when you read the registers properly you see 
that they have 1 thread per core.

John Baldwin

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