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Hi folks, This is the output for lscpu on my machine: Code: Architecture: i686 CPU op-mode(s): 32-bit, 64-bit Byte Order: Little Endian CPU(s): 4 On-line CPU(s) list: 0-3 Thread(s) per ...
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  1. #1
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    CPU socket


    Hi folks,

    This is the output for lscpu on my machine:

    Code:
    Architecture:          i686
    CPU op-mode(s):        32-bit, 64-bit
    Byte Order:            Little Endian
    CPU(s):                4
    On-line CPU(s) list:   0-3
    Thread(s) per core:    2
    Core(s) per socket:    2
    Socket(s):             1
    Vendor ID:             GenuineIntel
    CPU family:            6
    Model:                 42
    Stepping:              7
    CPU MHz:               800.000
    BogoMIPS:              5587.33
    Virtualisation:        VT-x
    L1d cache:             32K
    L1i cache:             32K
    L2 cache:              256K
    L3 cache:              4096K
    Could anyone please explain the meaning of the Core(s) per socket and Socket(s) fields?

    I imagine all the CPUs are in the same socket, so I don't understand why the Core(s) per socket field doesn't match the overall cores count (i.e. 4 CPUs x 2 cores = 8 ).

    Thanks

  2. #2
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    You're using hyper threading, therefor each core counts as 2 cpus.

  3. #3
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    I don't think that's correct. Core and CPUs are two different concepts. CPU is a synonim of processor. A core is a basic element of a processor. Also that doesn't hold with the case in the following post.

  4. #4
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    This is the output for lscpu on another (much more powerful) machine:

    Code:
    Architecture:          x86_64
    CPU op-mode(s):        32-bit, 64-bit
    Byte Order:            Little Endian
    CPU(s):                32
    On-line CPU(s) list:   0-31
    Thread(s) per core:    2
    Core(s) per socket:    8
    CPU socket(s):         2
    NUMA node(s):          2
    Vendor ID:             GenuineIntel
    CPU family:            6
    Model:                 45
    Stepping:              7
    CPU MHz:               2699.989
    BogoMIPS:              5399.28
    Virtualization:        VT-x
    L1d cache:             32K
    L1i cache:             32K
    L2 cache:              256K
    L3 cache:              20480K
    NUMA node0 CPU(s):     0-7,16-23
    NUMA node1 CPU(s):     8-15,24-31

  5. #5
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    My best guess is that each CPU has itsown socket. So the first lscpu output is suggesting that the whole system has 4 sockets and 2 cores per socket. The second (where it is explicitly called CPU socket(s)) refer to a 64 sockets platform (what the hell!) with 8 cores per socket.

    Any objection/confirmation is very welcome.

  6. #6
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    Quote Originally Posted by stefano913 View Post
    My best guess is that each CPU has itsown socket. So the first lscpu output is suggesting that the whole system has 4 sockets and 2 cores per socket. The second (where it is explicitly called CPU socket(s)) refer to a 64 sockets platform (what the hell!) with 8 cores per socket.

    Any objection/confirmation is very welcome.
    No. What I said in the first response is correct.

    Sockets are physical CPU modules that are plugged into the motherboard. Most desktop systems have 1 socket, most servers have 1 or 2 sockets, very expensive servers have 4 or (very rarely) more sockets.
    CPUs refers to the number of logical processing units your system has. In your case, you're using hyper threading, so 2 thread per core. 2 threads x 2 cores x 1 socket = 4 CPUs.

  7. #7
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    Yes, you're right. So a CPU is a logical processor whilst the core is a phisical processor.

    Thanks mizzle.

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