use all cores of CPU

I want to use parallel computing on matlab, i have i7-960 http://ark.intel.com/fr/products/37151/Intel-Core-i7-960-Processor-8M-Cache-3_20-GHz-4_80-GTs-Intel-QPI CPU with 4 cores and 8 threads, when i run feature('numCores') command in matlab, i obtain this

feature('numCores') 
MATLAB detected: 3 physical cores.
MATLAB detected: 6 logical cores.
MATLAB was assigned: 6 logical cores by the OS.
MATLAB is using: 3 logical cores.
MATLAB is not using all logical cores because hyper-threading is enabled.

ans =

       3

why matlab detect just juste 3 physical cores ! and how can i use all logical and physical cores for parallel computing. thanks.

[Titus Edelhofer]

Maybe one core is broken? :)

In fact, I have no idea how this can happen ...

Answer 1

[Ed Mitchell]

For people that are finding this MATLAB answer while searching more generally for how MATLAB manages the number of cores and hyperthreading, please refer to the following MATLAB Answer for more details.

Hyperthreading & Number of Cores

Answer 2

[Mehdi F]

To use all logical processes (number of threads) you need to change the NumWorkers in the matlab setting. in matlab 2018 menu follow this: Preferences >> Parallel Computing Toolbox>> Cluster Profile Manager >> click "Edit" on the bottom right >> Set "NumWorkers" to the number of logical process, 8 in your case. >> Done >> close and apply