With multicore CPUs it’s easy for newbies to get confused when faced with questions like;
1. How many physical CPUs does the server have?
2. How many cores on each CPU? Duo/Quad
In Linux it’s actually quite easy to get this info.
You could go through the /var/log/dmesg file or the /proc/cpuinfo file. For this tutorial we’ll look at the /proc/cpuinfo file.
Physical CPU count?
Run “cat /proc/cpuinfo | grep “physical id” | sort | uniq | wc -l”.
[root@bender ~]# cat /proc/cpuinfo | grep “physical id” | sort | uniq | wc -l
2
How many cores?
Run “cat /proc/cpuinfo | grep “cpu cores” | uniq”.
[root@kmigb000 ~]# cat /proc/cpuinfo | grep “cpu cores” | uniq
cpu cores      : 2
2 mean that each physical CPU has 2 cores on it. If cpu cores was 1 then the CPU’s single core.
How many virtual processors?
Run “cat /proc/cpuinfo | grep “^processor”"
[root@bender ~]# cat /proc/cpuinfo | grep “^processor”
processor      : 0
processor      : 1
processor      : 2
processor      : 3
That’s about right, 2 physical CPUs x 2 cores each = 4 virtual processeors.
However, it’s a bit different for HT (Hyper-Threading). If you get
cpu core = 1 but the virtual processors = 2 then the CPU’s running HT.
HT will only work with the SMP kernel.
