Hyperthreading hurts 5.3?

Bryan Fullerton fehwalker at gmail.com
Wed Jan 12 12:17:39 PST 2005

On Wed, 12 Jan 2005 00:02:37 -0500, Bryan Fullerton <fehwalker at gmail.com> wrote:
 > I'm experiencing some strangeness with a uniproc HTT-capable machine
> and SATA with either SMP or non-SMP kernels, so I'll try turning off
> HTT in the BIOS later this week and see if that helps.

Well, this is interesting. I disabled HTT in the BIOS and rebooted
with a SMP kernel. As expected, there is only one CPU available after
boot. However, FreeBSD still detects that the CPU is HTT-capable and
prints the following in dmesg output:

CPU: Intel(R) Pentium(R) 4 CPU 2.80GHz (2793.01-MHz 686-class CPU)
  Origin = "GenuineIntel"  Id = 0xf33  Stepping = 3
  Hyperthreading: 2 logical CPUs

If my sig11 issue doesn't recur now that HTT is off I'll go back to a
non-SMP kernel and confirm there are no issues there too.


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