Can a system have processors both with and without Hyper Threading?

Is is ever possible that a given computer has several processors among which only some have Hyper Threading technology and others do not?

My problem is that I use hardcore code like here for identifying which logical processors map to which physical cores. This code misbehaves when run in a virtual machine. My current intent is to first check whether the processor has Hyper Threading at all but I need to be sure that all other processors in the system also have (or not have) Hyper Threading.

Is it possible that only some processors in a system have Hyper Threading and others do not?

sharptooth

Posted 2009-09-17T07:40:54.953

Reputation: 831

This should probably be asked at stackoverflow.com – nik – 2009-09-17T09:19:31.277

Nope, that's not programming related, it's a pure hardware problem. – sharptooth – 2009-09-17T09:34:24.130

Answers

I think the most common kind of multi CPU support is Symmetric Multiprocessing (SMP) which requires identical processors. I believe this is true for Windows and most Linux distributions.

Dave Webb

Posted 2009-09-17T07:40:54.953

Reputation: 10 126

right - mixing CPUs is highly frowned-upon; they need to bethe same everything - cache, speed, number of cores, etc – warren – 2009-09-17T10:58:05.773

@warren They sometimes need to be the same revision number of a particular processor as a friend of mine found out to his cost. I remember seeing a chart he found showing which revisions of a Pentium II-300 would SMP happily together. – Dave Webb – 2009-09-17T11:03:30.393