Output for a Core i5 laptop: CPU model: Intel(R) Core(TM) i5-2520M CPU 2. 28 HTT Hyper Threading Yes 29 TM Thermal Monitor Yes 30 IA-64 Intel 64-bit Architecture Implementation No 31 SBF Signal Break on FERR. Output for a high-performance server: CPU model: Intel(R) Xeon(R) CPU X5650 2.67GHzĢ CPU, 6 physical cores per CPU, total 24 logical CPU units CPUInfo v2.1.3 - Freeware Processor information (CPU 1). Print nb_cpu,"CPU,",nb_cores,"physical cores per CPU, total",nb_units,"logical CPU units" \ Here is an inline awk script to pretty-print and extract relevant data from /proc/cpuinfo : cat /proc/cpuinfo | \ If your system has the lscpu tool (part of recent util-linux), it would output a more human-readable summary of the CPUs installed, for example: Thread(s) per core: 2 About 10 seconds later the same script is repeated with hyper threading turned on. ' TL DR: unfixed Skylake and Kaby Lake processors could, in some situations, dangerously misbehave when hyper-threading is enabled. A logical CPU can be a hyperthreading sibling, a shared core. Below you can see the CPU utilization when hyper-threading is turned off and a CPU stress test is performed. Henrique de Moraes Holschuh has posted an advisory about a processor/microcode defect recently identified on Intel Skylake and Intel Kaby Lake processors with hyper-threading enabled. /proc/cpuinfo is a read only file, which shows each logic CPU with a unique processor number. Note that some Intel processors (the i5 included) use hyperthreading, a system where a single processor has (for example) 2 pyhsical cores, but will provide 4 logical cores - allowing the operating system to treat the processor as having more cores than it really does. Display of CPUs when Hyper-Threading is turned off/on. In other words, they represent the four cores of a single Intel i3 CPU.Īlso, as noted on this post (which is not exactly a duplicate but closely related), those cores are logical as well – the CPU has two cores physically but supports hyperthreading.
(Note that they all have the same physical id.) I recently purchased one such system and am still under the charm of cat /proc/cpuinfo telling me that I have two CPUs in my box. On CPUs that include technologies such as hyperthreading, the number of logical cores may be. The entries are logical processors objects used by the kernel internally, not necessarily tied to physical devices. Returns the total number of logical CPU cores.
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