Hyperthreading in non-SMP systems

Steve Joynt joynt at bigpond.net.au
Fri May 2 20:31:21 PDT 2003


Is it possible to have Hyperthreading enabled in non-SMP systems? According
to LINT the HTT option requires SMP and APIC_IO, but when I include both of
those in my P4 3.06GHz system it panics on startup with:

panic: pmap_bootstrap: no local apic!
mp_lock = 0000000c; cpuid = 0; lapic.id = 00000000

I have hyperthreading enabled in the bios, and when booting with a standard
kernel I get the following:

CPU: Intel(R) Pentium(R) 4 CPU 3.06GHz (3073.65-MHz 686-class CPU)
  Origin = "GenuineIntel"  Id = 0xf27  Stepping = 7
  Hyperthreading: 2 logical CPUs

but there's no further messages about enabling both cpus. Does this mean
that HTT is only supported on systems with have multiple (physical) cpus?

- Steve

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