On Tue, Oct 10, 2006 at 01:59:39PM -0400, Garance A Drosihn wrote: > At 10:15 AM +1000 10/10/06, Arthur Hartwig wrote: > >ext kumaresh pandian wrote: > >>Hi all > >> > >> > >> How do i Find if the CPU is Hyperthreading enabled or not? I have > >>tried using the mtables but i'm not able to figure it out. > >> > >Look for the HTT bit in the CPU features displayed when FreeBSD starts > >up. Here's an example from one of my systems, HTT is third from the > >right hand end of the CPU features list. > > > >Copyright (c) 1992-2005 The FreeBSD Project. > >Copyright (c) 1979, 1980, 1983, 1986, 1988, 1989, 1991, 1992, 1993, 1994 > > The Regents of the University of California. All rights reserved. > >hartwig 1 10.09.2006-151040MPTable: <OEM ID PRODUCT ID > > >Timecounter "i8254" frequency 1193182 Hz quality 0 > >CPU: Intel(R) Xeon(TM) CPU 2.80GHz (2794.59-MHz 686-class CPU) > > Origin = "GenuineIntel" Id = 0xf27 Stepping = 7 > > > >Features=0xbfebfbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,CLFLUSH,DTS,ACPI,MMX,FXSR,SSE,SSE2,SS,HTT,TM,PBE> > > Features2=0x4400<CNTX-ID,<b14>> > > Hyperthreading: 2 logical CPUs > >real memory = 2147483648 (2048 MB) > >avail memory = 2100936704 (2003 MB) > > Huh. > I just got a dual-core Athlon64 machine, and the features list for > it says: > > Features=0x178bfbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP, > MTRR,PGE,MCA,CMOV,PAT,PSE36,CLFLUSH,MMX,FXSR,SSE,SSE2, > HTT> > --- > > My dmesg does not have the line about "Hyperthreading: 2 logical CPUs", > though. But I had been pretty sure the Athlon64 chips didn't have any > hyperthreading support. Why is the HTT there?
To trick license managers and schedulers that know HTT, but not true multi-core. They report the physical cores a logical cores and then add an additional flag saying that they are really physical. -- Brooks
pgpgPvIME2tzj.pgp
Description: PGP signature
