Messages in this thread | | | From | Andrew Theurer <> | Subject | Hyperthreading and physical/logical CPU identification | Date | Mon, 29 Apr 2002 13:31:53 -0500 |
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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 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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