Shulou(Shulou.com)06/02 Report--

In this issue, the editor will bring you what hyperthreading means. The article is rich in content and analyzes and narrates it from a professional point of view. I hope you can get something after reading this article.

First of all, hyperthreading is a patented technology of Intel, but it was developed by Digital equipment Company (Digital Equipment Corporation) in 2002. Second, this technique can execute fragments of multiple program processes at the same time (this fragment is called thread), which is a kind of instruction-level instruction level parellelism. Find a diagram that clearly explains how hyper-threaded CPU works and improves efficiency.

The upper half of the picture is the CPU without hyperthreading, and the lower half is the CPU without hyperthreading.

From the operating system's point of view, the hyper-threaded CPU executes thread 1 and thread 2 at the same time, followed by yellow, blue and orange colors indicating the time slice distribution of CPU, and finally the result. It is obviously better than CPU without hyperthreading. Processors using this technology need corresponding support from motherboard and operating system. The hardware needs to turn on firmware support in BIOS/UEFI. By default, it is generally enabled.

How to check if hyperthreading is used in the operating system? In the Windows operating system, view the task manager, as shown below:

In the figure above, 12 small squares represent 12 logical CPU. The following text shows that there are only 1 slot, 6 cores and 12 logical processors, indicating that each kernel provides hyperthreading and becomes 12 cores.

Within CentOS 7, you can run the command to view.

# dmidecode | grep Count Core Count: 6 Thread Count: 12

From the output information, we can see that 6 cores, 12 threads, is also enabled hyperthreading.

# lscpu// output as follows: Architecture: x86_64CPU op-mode (s): 32-bit 64-bitByte Order: Little EndianCPU (s): 12On-line CPU (s) list: 0-11Thread (s) per core: 2Core (s) per socket: 6Socket (s): 1NUMA node (s): 1Vendor ID: GenuineIntelCPU family: 6Model: 158Model name: Intel (R) Core ( TM) i7-8850H CPU @ 2.60GHzStepping: 10CPU MHz: 999.914CPU max MHz: 4300.0000CPU min MHz: 800.0000BogoMIPS: 5184.00Virtualization: VT-xL1d cache: 32KL1i cache: 32KL2 cache: 256KL3 cache: 9216KNUMA node0 CPU (s): 0- 11Flags: 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 art arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc aperfmperf eagerfpu pni pclmulqdq dtes64 monitor ds_cpl vmx smx est tm2 ssse3 sdbg fma cx16 xtpr pdcm pcid sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand lahf_lm abm 3dnowprefetch epb invpcid_single intel_pt ssbd ibrs ibpb stibp tpr_shadow vnmi flexpriority Ept vpid fsgsbase tsc_adjust bmi1 hle avx2 smep bmi2 erms invpcid rtm mpx rdseed adx smap clflushopt xsaveopt xsavec xgetbv1 dtherm ida arat pln pts hwp hwp_notify hwp_act_window hwp_epp md_clear spec_ctrl intel_stibp flush_l1d

Hyperthreading information can also be read from the output of the lscpu command:

CPU (s): 12

On-line CPU (s) list: 0-11, numbered from 0 to 11

Thread (s) per core: 2, each core provides 2 threads, which, to put it bluntly, is hyperthreading

Core (s) per socket: 6, with 6 cores per slot

Socket (s): 1, 1 slot

# grep-I HT / proc/cpuinfoflags: 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 cx16 xtpr pdcm pcid dca sse4_1 sse4_2 popcnt aes lahf_lm arat epb dts tpr_shadow vnmi flexpriority ept vpid

It turns out that the ht in this is hyperthreading.

The above is the meaning of hyperthreading hyperthreading shared by the editor. If you happen to have similar doubts, please refer to the above analysis to understand. If you want to know more about it, you are welcome to follow the industry information channel.

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