a common hyperthreading misconception.

Despite having been around for seven years now, I still see a common misconception surrounding hyper-threading. People look at /proc/cpuinfo, see ‘ht’ in the flags line, and think “hey, I don’t have hyper-threading, /proc/cpuinfo is wrong!”.

But this isn’t the case. The ‘ht’ flag doesn’t signify the presence of hyper-threading or not. It signifies the presence of the ability to say yes or no as to whether the processor has any siblings. Basically “If I call this cpuid function, can I trust the results?”. This cpuid function is present in all intel processors since the Pentium 4.

So seeing a cpu with ‘ht’ in the flags, but no siblings is perfectly normal, and has been for all this time, but some people just don’t seem to get it.