Messages in this thread | | | Date | Mon, 29 Apr 2002 16:14:33 -0700 (PDT) | From | Jauder Ho <> | Subject | RE: Hyperthreading and physical/logical CPU identification |
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Well, you could always take CPUs out... :)
--Jauder
On Mon, 29 Apr 2002, Grover, Andrew wrote:
> > From: Andrew Theurer [mailto:habanero@us.ibm.com] > > 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?) > > Well the two alternatives are, either A) turning on hyperthreading enabled > the two virtual processors or B) turning on hyperthreading somehow enabled > the other two processors, right? > > I would think B would be highly unlikely. > > Anyone else who actually has HT hardware care to comment? ;-) > > Regards -- Andy > - > 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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