Hyper-Threading with T30 on linux

[printf]

under linux, "cat /proc/cpuinfo" says the "ht" flag is enabled on my processor.
recomplied the kernel (version 3.7.4) with the following settings:

[*] Symmetric multi-processing support
[*] SMT (Hyperthreading) scheduler support

note: enabling the first also turned on the "Enable MPS table" feature, is that relevant to this problem?

but when i run "dmesg | grep Hyper" it says hyper threading is disabled.

question is that is ht possible on a t30?
if i read correctly, the only thing needed is a ht capable processor and a supporting operating system - chipset is irrelevant
also there is no setting to turn on/off ht from bios

[Medessec]

I'm not completely certain, but I recall that none of the processors equipped with the T30(Northwood-core Mobile P4s ranging from 1.6-2.2GHz) are capable of Hyper-Threading. That's why there's no setting in the BIOS.

There is software Hyper-threading, but I don't know anything about that, and I imagine it's far less efficient and beneficial compared to Intel's native Hyper-threading.

[ajkula66]

Correct.

No HT on T30 or any other ThinkPad of that era.

The only one that takes HT processors (desktop variety, though) is G41.

[craigmontHunter]

I'm not sure why this happens, but I have seen it before where the processor shows the hyperthreading flag as existing and disabled rather than just not showing it at all. This is a shot in the dark, but I wonder if the software bases the flags off the codename (or family/model/stepping...) because there were a limited number of desktop northwoods that supported hyperthreading.

The chipset is very relevant, it has to support hyperthreading, and even then there has to be a bios option to enable it as it is normally disabled by default, however the bios option won't necessarily show up unless the processor supports hyperthreading.

[Medessec]

The only Northwoods that supported HT were the very late ones, and I believe they were very high clocked (3GHZ+). And they were only desktop processors.

I believe pretty much any P4-M(mobile Pentium 4s) were not made to support Hyper Threading, neither did they feature it. Some chipsets might allow for it, and some BIOS will support it, explaining why you'd see "Hyperthreading: Disabled" grayed out in a BIOS of a computer that clearly wouldn't support it.

But the T30's chipset and entire range of CPUs, i'm pretty sure, aren't capable of HT.