Linux view the number of physical CPUs, the number of cores, the number of logical CPUs

(i) Conceptual

① Physical CPU

Number of CPUs on slots in actual server
Number of physical CPUs, several physical IDs can be counted

② Logical CPU

/proc/cpuinfo used to store CPU hardware information.
The information content lists the specification of processor 0–processor N respectively. Note here that n is the logical number of CPUs
In general, we think that a CPU can have multi-core, plus Intel's Hyper-Threading Technology (HT), which can logically be divided into a second number of CPU core out
Logical CPUs = number of physical CPUs x CPU cores This metric value x 2 (if HT is supported and turned on)
Note: Linux top view CPU is also the number of logical CPUs

③CPU Nuclear number

The number of chipsets that can process data on a single CPU, such as the current i5 760, is a dual-core four-thread CPU, and i5 2250 is a quad-core four-threaded CPU
In general, the number of physical CPUs x per kernel should equal the number of logical CPUs, if not equal, the server's CPU support Hyper-Threading Technology

㈡ View CPU Information

When we cat/proc/cpuinfo,
CPUs with the same core ID are the same core Hyper-threading
CPUs with the same physical ID are threads or cores encapsulated by the same CPU

Example

# Total Kernel = number of physical CPUs X number of cores per physical CPU
# Total Logical CPUs = number of physical CPUs x number of cores per physical CPU x Hyper-Threading

# View the number of physical CPUs
cat/proc/cpuinfo| grep "Physical ID" | Sort| uniq| Wc-l

# View the number of cores in each physical CPU (that is, the kernel number)
cat/proc/cpuinfo| grep "CPU Cores" | Uniq

# View the number of logical CPUs
cat/proc/cpuinfo| grep "Processor" | Wc-l

#查看CPU信息 (model)
Cat/proc/cpuinfo | grep name | Cut-f2-d: | Uniq-c