To activate or deactivate a core using operating system commands, you must know the number or numbers of the virtual or logical processors associated with that core. This task provides instructions for calculating those numbers.
Your server has two, four, or eight sockets numbered 0 through 1, 3, or 7.
Each socket has 18 cores numbered 0 through 17.
Each core has one or two virtual processors associated with it, depending on whether hyperthreading is enabled or not. To deactivate a core, you must deactivate both virtual processors associated with that core.
You can also use operating system commands to display virtual processor numbers. See:
For example, to calculate the number of the first virtual processor for core 2 on socket 2:
2 x 18 +2 = 38
For example: 2 x 18 +2 = 38
For example, in a 4 socket system: 4 x 18 = 72
For example: 72 + 38 = 110
The quotient is the socket number.
The remainder is the core number.
For example 38 / 18 = 2 with a remainder of 2. Virtual processor 38 runs on socket 2, core 2.
Divide the core number by the number of processors per core. This produces a whole number and a decimal. For example:
38 / 18 = 2.111111111111111
The whole number is the socket. Subtract it from the total. For example:
2.111111111111111 - 2 = .111111111111111
Multiply the decimal by 18 to find the remainder, which is the core number on this socket. For example:
.111111111111111 x 18 = 2.
Core 38 is processor 2, core 2.