在linux下面可以查看一下超线程是否开启
命令：dmidecode -t processor
[root@cluster ~]# dmidecode -t processor
# dmidecode 2.12
SMBIOS 2.8 present.
Handle 0x0400, DMI type 4, 42 bytes
Processor Information
Socket Designation: CPU1 这里可以查看机器有几个CPU
Type: Central Processor
Family: Xeon
Manufacturer: Intel
ID: F2 06 03 00 FF FB EB BF
Signature: Type 0, Family 6, Model 63, Stepping 2
Flags:
FPU (Floating-point unit on-chip)
VME (Virtual mode extension)
DE (Debugging extension)
PSE (Page size extension)
TSC (Time stamp counter)
MSR (Model specific registers)
PAE (Physical address extension)
MCE (Machine check exception)
CX8 (CMPXCHG8 instruction supported)
APIC (On-chip APIC hardware supported)
SEP (Fast system call)
MTRR (Memory type range registers)
PGE (Page global enable)
MCA (Machine check architecture)
CMOV (Conditional move instruction supported)
PAT (Page attribute table)
PSE-36 (36-bit page size extension)
CLFSH (CLFLUSH instruction supported)
DS (Debug store)
ACPI (ACPI supported)
MMX (MMX technology supported)
FXSR (FXSAVE and FXSTOR instructions supported)
SSE (Streaming SIMD extensions)
SSE2 (Streaming SIMD extensions 2)
SS (Self-snoop)
HTT (Multi-threading)
TM (Thermal monitor supported)
PBE (Pending break enabled)
Version: Intel(R) Xeon(R) CPU E5-2640 v3 @ 2.60GHz
Voltage: 1.3 V
External Clock: 8000 MHz
Max Speed: 4000 MHz
Current Speed: 2600 MHz
Status: Populated, Enabled
Upgrade: Socket LGA2011-3
L1 Cache Handle: 0x0700
L2 Cache Handle: 0x0701
L3 Cache Handle: 0x0702
Serial Number: Not Specified
Asset Tag: Not Specified
Part Number: Not Specified
Core Count: 8
Core Enabled: 8
Thread Count: 16
Characteristics:
64-bit capable
Multi-Core
Hardware Thread
Execute Protection
Enhanced Virtualization
Power/Performance Control
Handle 0x0401, DMI type 4, 42 bytes
Processor Information
Socket Designation: CPU2 我这个机器有两个CPU
Type: Central Processor
Family: Xeon
Manufacturer: Intel
ID: F2 06 03 00 FF FB EB BF
Signature: Type 0, Family 6, Model 63, Stepping 2
Flags:
FPU (Floating-point unit on-chip)
VME (Virtual mode extension)
DE (Debugging extension)
PSE (Page size extension)
TSC (Time stamp counter)
MSR (Model specific registers)
PAE (Physical address extension)
MCE (Machine check exception)
CX8 (CMPXCHG8 instruction supported)
APIC (On-chip APIC hardware supported)
SEP (Fast system call)
MTRR (Memory type range registers)
PGE (Page global enable)
MCA (Machine check architecture)
CMOV (Conditional move instruction supported)
PAT (Page attribute table)
PSE-36 (36-bit page size extension)
CLFSH (CLFLUSH instruction supported)
DS (Debug store)
ACPI (ACPI supported)
MMX (MMX technology supported)
FXSR (FXSAVE and FXSTOR instructions supported)
SSE (Streaming SIMD extensions)
SSE2 (Streaming SIMD extensions 2)
SS (Self-snoop)
HTT (Multi-threading)
TM (Thermal monitor supported)
PBE (Pending break enabled)
Version: Intel(R) Xeon(R) CPU E5-2640 v3 @ 2.60GHz
Voltage: 1.3 V
External Clock: 8000 MHz
Max Speed: 4000 MHz
Current Speed: 2600 MHz
Status: Populated, Enabled
Upgrade: Socket LGA2011-3
L1 Cache Handle: 0x0703
L2 Cache Handle: 0x0704
L3 Cache Handle: 0x0705
Serial Number: Not Specified
Asset Tag: Not Specified
Part Number: Not Specified
Core Count: 8
Core Enabled: 8
Thread Count: 16 这个地方显示如果开超线程，那就应该是16核心，不开则为8核心。
Characteristics:
64-bit capable
Multi-Core
Hardware Thread
Execute Protection
Enhanced Virtualization
Power/Performance Control
我们还需要一步命令。查看cpu的一共核心是多少。
[root@cluster ~]# cat /proc/cpuinfo
查看最后显示的processor就可以，这里等于32个。那我们简单计算一下我机器2个cpu，没开超线程应该是16，开了那就是32核心。这个是从0开始计算的，所以我的机器，是开了超线程的。
processor : 31
vendor_id : GenuineIntel
cpu family : 6
model : 63
model name : Intel(R) Xeon(R) CPU E5-2640 v3 @ 2.60GHz
stepping : 2
cpu MHz : 2600.138
cache size : 20480 KB
physical id : 1
siblings : 16
core id : 7
cpu cores : 8
apicid : 31
initial apicid : 31
fpu : yes
fpu_exception : yes
cpuid level : 15
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx pdpe1gb rdtscp lm constant_tsc arch_perfmon pebs bts rep_good xtopology nonstop_tsc aperfmperf pni pclmulqdq dtes64 monitor ds_cpl vmx smx est tm2 ssse3 fma cx16 xtpr pdcm pcid dca sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand lahf_lm abm ida arat epb xsaveopt pln pts dts tpr_shadow vnmi flexpriority ept vpid fsgsbase bmi1 avx2 smep bmi2 erms invpcid
bogomips : 5199.24
clflush size : 64
cache_alignment : 64
address sizes : 46 bits physical, 48 bits virtual
power management:
[root@cluster ~]#
