Number of physical CPU, logical CPU, and CPU cores in Linux

Source: Internet
Author: User

Linux distinguishes physical CPU, logical CPU, and CPU cores (I) concept ① physical CPU the number of physical CPUs in the actual Server slot the number of physical CPUs, there are several non-Repeated physical IDs. ② logical CPU Linux users are certainly familiar with the/proc/cpuinfo file. it lists the specifications of processor 0-n separately. It should be noted that if you think n is the actual number of CPUs, it would be a big mistake. We think a cpu can have multiple cores, coupled with intel's hyper-Threading Technology (HT ), logically, you can double the number of cpu cores. Logical cpu count = physical cpu count x cpu cores. The specification value is x 2 (if ht is supported and enabled) Note the following: in Linux, the top view CPU is also the number of logical CPUs ③ Number of CPU cores the number of chipsets on which data can be processed by one CPU, such as the current i5 760, it is a dual-core CPU with four threads, while i5 2250 is a four-core CPU with four threads. Generally, the number of physical CPUs × the number of each core should be equal to the number of logical CPUs. Otherwise, indicates that the CPU of the server supports hyper-Threading Technology (ii) view CPU information. When we use cat/proc/cpuinfo, the CPU with the same core id is the same CPU with the same physical id. threads or cores encapsulated by the same CPU (iii) Example 1 view the number of physical CPUs [plain] # cat/proc/cpuinfo | grep "physical id" | sort | uniq | wc- l 2 ② view the number of logical CPUs [plain] # cat/proc/cpuinfo | grep "processor" | wc-l 24 ③ view CPU cores [plain] # cat/proc /cpuinfo | grep "cores" | uniq 6 I Should Have 2 CPUs here, each Cpu has 6 cores, which should be Intel's U and support hyper-threading.

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