GNU/Linux Ubuntu showing 2 cores - CPU0 and CPU1

Discussion in 'Laptop Hardware' started by casainho, Jul 30, 2008.

  1. casainho

    casainho

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    Hello :)

    When I open the "System monitor" I see a graph of two different CPUs, the 0 and the 1. Is this Atom processor dual core?
     
    casainho, Jul 30, 2008
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  2. casainho

    KiNG

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    interesting, any chance of a screenshot?
     
    KiNG, Jul 30, 2008
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  3. casainho

    casainho

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    I am Portuguese - thats the language, like "Monitor de Sistema" :)
     
    casainho, Jul 30, 2008
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  4. casainho

    KiNG

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    mad, do you have any other testing programs to confirm this?
     
    KiNG, Jul 30, 2008
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  5. casainho

    macles

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    The Atom N270 has Hyperthreading, which is interpreted like two virtual cores by the system. You can check yourself using cat /proc/cpuinfo which will show this. Notice it says cores=1 but siblings=2.

    Code:
    processor       : 1
    vendor_id       : GenuineIntel
    cpu family      : 6
    model           : 28
    model name      : Intel(R) Atom(TM) CPU N270   @ 1.60GHz
    stepping        : 2
    cpu MHz         : 800.000
    cache size      : 512 KB
    physical id     : 0
    siblings        : 2
    core id         : 0
    cpu cores       : 1
     
    macles, Jul 30, 2008
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  6. casainho

    casainho

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    May be something wrong with ACPI... for example, I can't set them bellow to 800MHz - 50%.I would go to 12% or 25% as looks possible on this ACPI info...
     
    casainho, Jul 30, 2008
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  7. casainho

    casainho

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    Well, I did follow this guide for have cpu control:
    http://wiki.eeeuser.com/getting_ubuntu_ ... or_scaling

    I just see this:

    cas@cas-laptop:~$ cat /proc/cpuinfo
    processor : 0
    vendor_id : GenuineIntel
    cpu family : 6
    model : 28
    model name : Intel(R) Atom(TM) CPU N270 @ 1.60GHz
    stepping : 2
    cpu MHz : 1600.000
    cache size : 512 KB
    physical id : 0
    siblings : 2
    core id : 0
    cpu cores : 1
    fdiv_bug : no
    hlt_bug : no
    f00f_bug : no
    coma_bug : no
    fpu : yes
    fpu_exception : yes
    cpuid level : 10
    wp : yes
    flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe constant_tsc arch_perfmon pebs bts pni monitor ds_cpl est tm2 ssse3 xtpr lahf_lm
    bogomips : 3196.56
    clflush size : 64

    processor : 1
    vendor_id : GenuineIntel
    cpu family : 6
    model : 28
    model name : Intel(R) Atom(TM) CPU N270 @ 1.60GHz
    stepping : 2
    cpu MHz : 1600.000
    cache size : 512 KB
    physical id : 0
    siblings : 2
    core id : 0
    cpu cores : 1
    fdiv_bug : no
    hlt_bug : no
    f00f_bug : no
    coma_bug : no
    fpu : yes
    fpu_exception : yes
    cpuid level : 10
    wp : yes
    flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe constant_tsc arch_perfmon pebs bts pni monitor ds_cpl est tm2 ssse3 xtpr lahf_lm
    bogomips : 3191.98
    clflush size : 64

    cas@cas-laptop:~$
     
    casainho, Jul 30, 2008
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  8. casainho

    macles

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    Probably a bug in Ubuntu. You can also check N270 specs: http://download.intel.com/design/proces ... 320032.pdf

    Wait a second i just noticed that i have the same output with two processors, just never noticed it. So it's all good, HT is actually reported as 2 CPUs by cpuinfo.
     
    macles, Jul 30, 2008
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  9. casainho

    Felinux

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    Also Linpus see twu cpu, press "Ctrl+Alt+Canc" for start "System Monitor" utility and click on "System" or "Resources" tab.
    Only a simulation of HT tecnology.
     
    Felinux, Jul 30, 2008
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  10. casainho

    rjm

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    A cpu with hyperthreading enabled, such as the Atom, will appear to the operating system as having two cores. This is normal.

    The cpu does not, however, have two cores. There is a performance benefit to hyperhtreading, but it is not the same as true dual-core architecture.

    The dual core Atom will be released later this year.

    http://www.hexus.net/content/item.php?item=13494

    (Will that also be HT enabled and report as four cores? Apparently so.)
     
    rjm, Jul 30, 2008
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  11. casainho

    rory

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    Windows has 2 graphs in task manager for Processor usage.
    Rory
     
    rory, Jul 30, 2008
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  12. casainho

    Davidcowling

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    a cpu that hyperthreads basically tricks the system into thinking it has two cores.

    whilst this is faster than a basic cpu, having 2 physical cores will always be quicker.
     
    Davidcowling, Jul 31, 2008
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