To get number of logical processors using CPUID instruction

[hyunsoo]

Hi all,

I have Intel i9-10900 CPU equipped with 20 logical processors. It shows exactly 20 cores in 'htop' command but, `cpuid` instruction says that I have only 16 logical processors.

I ran the cpuid instruction like below.

```

...

asm volatile
("cpuid" : "=a" (regs[0]), "=b" (regs[1]), "=c" (regs[2]), "=d" (regs[3])
: "a" (i), "c" (0));

...

```

Could you give any comment?

Thanks

[McCalpinJohn · Accepted solution]

To make sure you are using the CPUID instruction correctly, I recommend http://www.etallen.com/cpuid.html as a reference.