CPU个数和核数的判断依据

一直听说多核，多cpu，但是一直没有具体明白怎么查看一台linux机器的这些信息。前段时间终于抽空学习了一下

CPU个数和核数的判断依据： 

1. physical id 个数为物理CPU的个数

2. core id 个数为核数

3. 逻辑CPU

# 总核数 = 物理CPU个数 X 每颗物理CPU的核数 

# 总逻辑CPU数 = 物理CPU个数 X 每颗物理CPU的核数 X 超线程数

1.具有相同core id的cpu是同一个core的超线程。 
2.具有相同physical id的cpu是同一颗cpu封装的线程或者cores。 

查看cpu型号
[root@localhost c_language]# cat /proc/cpuinfo | grep name | cut -f2 -d: | uniq -c
      4  Intel(R) Core(TM) i5-2520M CPU @ 2.50GHz
 
查看物理cpu颗数
通过/proc/cpuinfo 里面的physical id来判断物理CPU的个数
[root@localhost c_language]# cat /proc/cpuinfo | grep"physical id" | uniq |wc -l
1
# 查看每个物理CPU中core的个数(即核数)
[root@localhost c_language]# more /proc/cpuinfo | grep"cpu cores"| uniq
cpu cores             :2
 
# 查看逻辑CPU的个数
[root@localhost c_language]# more /proc/cpuinfo | grep"processor"| uniq|wc -l
4
[root@localhost c_language]#
 
 
[root@localhost c_language]# lscpu
Architecture:         x86_64              /*64位的X86架构*/
CPU op-mode(s):       32-bit, 64-bit
Byte Order:           Little Endian
CPU(s):               4                             /*逻辑CPU个数4*/
On-line CPU(s) list:  0-3
Thread(s) per core:   2                 /*每个核的超线程数是2*/
Core(s) per socket:   2                 /*每个CPU插槽核数/每颗物理CPU核数是2*/
Socket(s):            1
NUMA node(s):         1
Vendor ID:            GenuineIntel           /*CPU厂商*/
CPU family:           6
Model:                42
Stepping:             7
CPU MHz:              800.000            /*CPU主频是800M*/
BogoMIPS:             4989.12
Virtualization:       VT-x                /*cpu支持的虚拟化技术VT-x*/
L1d cache:            32K
L1i cache:            32K
L2 cache:             256K
L3 cache:             3072K
NUMA node0 CPU(s):    0-3