Linux & Hyperthreading

i wrote about this before, but it's ok, i'll write it again:

hyperthreading can be enabled through using an smp kernel - it will just appear as two cpus. any distro that can detect smp and install the correct kernel would theoretically work fine. (i think they detect it now; the last time i installed a big binary distro back in the day, you had to explicitly choose the smp kernel, so i'm not sure anymore)

however, Symmetric Multi Threading is not the same as Symmetric Multi Processing. there are instances (rare ones) where programs would run slightly slower with hyperthreading through smp. i have yet to see this happen, but it is possible because the way they manage parallel threads is not exactly the same.

hypertheading is an acpi-enabled feature. so actually, the _correct_ and most optimized way to enable hypertheading is to enable smp, and with any relatively recent acpi kernel patch, enable 'cpu enumeration' under acpi. however, for some reason or another, enabling cpu enumeration disables all the other acpi features. i didn't write acpi4linux so i don't know why, but they might be incompatible with each other, and perhaps fixing that is not on their list since a hypertheading laptop is not a common thing. i don't know.

but anyway, the problem is that we are on sager laptops, and we need those other acpi features like ac adapter, battery, processor throttling, lid switch, etc. and it's not like we can enable cpu enumeration and use apm for the other stuff, because acpi and apm don't play nice - you can only have one or the other. (mutually exclusive)

so it's really not worth it to use acpi's cpu enumeration. mine works perfectly fine with just smp, and acpi managing all the other laptop features.

now that i've rambled on, i suppose the final answer is: yes. it is, for all intents and purposes, smp. i can't say for sure about automatic detection, as it varies from distro to distro. but certainly if a distro cannot autodetect smp, it would give you the option to choose an smp kernel.