上圖顯示超執行緒(Hyper Threading)被關掉了因此:
- Physical CPUs active = 4:實體核心數目是4個
- Logical CPUs active = 4:邏輯核心數目也是4個
$ sysctl -a | grep hw.*cpu
hw.ncpu: 8
hw.activecpu: 4
hw.physicalcpu: 4
hw.physicalcpu_max: 4
hw.logicalcpu: 4
hw.logicalcpu_max: 8
hw.cputype: 7
hw.cpusubtype: 8
hw.cpu64bit_capable: 1
hw.cpufamily: 280134364
hw.cpufrequency: 2300000000
hw.cpufrequency_min: 2300000000
hw.cpufrequency_max: 2300000000
hw.cputhreadtype: 1
- hw.physicalcpu:The number of physical processors available in the current power management mode.
- hw.logicalcpu:The number of logical processors available in the current power management mode.
注意,這個方法並不是從EFI直接關掉hyperthreading,所以隨時都可以此軟體決定核心數目或是超執行緒要不要啟動~目前還是找不到直接進去Mac EFI的方法
跟hyper-threading有關的文章
- Intel Hyper Threading Performance With A Core i7 On Ubuntu 18.04 LTS
- Leaked Benchmarks Suggest Intel Will Drop Hyper-Threading from Core i7
- Would turning off hyper threading on an Intel Chip increase single core performance?
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