Linux上如何查看物理CPU个数，核数，线程数

标签：gpu   process   内核   man   package   instr   int   manage   查看cpu   

首先，看看什么是超线程概念

超线程技术就是利用特殊的硬件指令，把两个逻辑内核模拟成两个物理芯片，让单个处理器都能使用线程级并行计算，进而兼容多线程操作系统和软件，减少了CPU的闲置时间，提高的CPU的运行效率。
超线程技术是在一颗CPU同时执行多个程序而共同分享一颗CPU内的资源，理论上要像两颗CPU一样在同一时间执行两个线程，虽然采用超线程技术能同时执行两个线程，但它并不象两个真正的CPU那样，每个CPU都具有独立的资源。当两个线程都同时需要某一个资源时，其中一个要暂时停止，并让出资源，直到这些资源闲置后才能继续。因此超线程的性能并不等于两颗CPU的性能。

其次，看看物理CPU个数，核数以及线程数的关系

总核数 = 物理CPU个数 * 每颗物理CPU的核数
总逻辑CPU数 = 物理CPU个数 * 每颗物理CPU的核数 * 超线程数

上述公式中，逻辑CPU数即线程数

如何查看CPU物理个数

# grep ‘physical id‘ /proc/cpuinfo | sort -u

physical id    : 0
physical id    : 1

如何查看每个物理CPU的核数

# grep ‘core id‘ /proc/cpuinfo | sort -u | wc -l

8

如何查看总的逻辑CPU个数

# grep ‘processor‘ /proc/cpuinfo | sort -u | wc -l

32

32/8/2=2，可见该CPU支持并已打开超线程。

如何查看CPU的型号

# dmidecode -s processor-version

Intel(R) Xeon(R) CPU E5-2658 @ 2.10GHz
Intel(R) Xeon(R) CPU E5-2658 @ 2.10GHz

关于物理CPU，核数以及超线程的区别

A core is the most basic computational unit of a processor. A processor is made up of one or more cores. Tradition processors had only one core while modern processors have multiple cores.

A core consists of an ALU, CU, and a set of registers.

A core consists of two levels of caches called L1 and L2 which is there in each core.

A processor consists of a cache that is shared by call cores called L3 cache. It is common to all cores.

A processor depending on the architecture can consist of a memory controller and an input/output controller.

Certain processor packages consist of Graphics Processing Units (GPU) as well.

A core that does not have hyper-threading can execute only one instruction at a time while a multicore processor made up of several cores can execute several instructions parallel. If a processor is made up of 4 cores that do not support hyper threading then that processor can execute 4 instructions at the same time.

A core having hyper-threading technology has redundant functional units so that they can execute multiple instructions at a time. For example, a core with 2 threads can execute 2 instructions at the same time hence a processor with 4 such cores can execute 2×4 instructions parallel. These threads are usually called logical cores and the task manager of Windows generally show the number of logical cores but not the physical cores.

Linux上如何查看物理CPU个数，核数，线程数

标签：gpu   process   内核   man   package   instr   int   manage   查看cpu   

原文地址：http://www.cnblogs.com/xiaojianblogs/p/6209382.html