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    SubjectHyperthreading and physical/logical CPU identification
    Date
    Hello all,

    I would like to know if there is any way to confirm that I have
    hyperthreading enabled, and my P4 CPUs are hyperthreaded. Actually, from
    something like /proc/cpuinfo, I'd like to figure out if I am seeing 2/4
    physical/logical processors, as a result from hyperthreading, or 4/4
    physical/logical processors with no hyperthreading. I know, "If it's double
    the number of physical processors, well you have hyperthreading enabled."
    The problem is, I have 4 physical processors, but kernel.org kernels so far
    do not recognize all of them. 2.4.18 will find 3, while 2.5.11 will find
    only 2 (BIOS hyperthreading support off, no acpismp=force). However, on
    2.5.11, if I enable hyperthreading (thru BIOS and acpismp=force, I see 4
    processors.

    I would very much like to believe that in this configuration, I am only
    running on 2 physical, 4 logical processors, but I am getting a 31%
    improvement (netbench) when hyperthreading is enabled. Thats why I want to
    confirm I am really only using 2 physical, 4 logical processors. Is there
    any way I can do this? (dmesg? /proc/cpuinfo?)

    Thanks

    Andrew Theurer
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