hyperthreading CPU and broken scheduling?

Wojciech Puchar wojtek at wojtek.tensor.gdynia.pl
Sun Nov 18 02:16:14 PST 2007

i have machune with intel's CPU with hyperthreading.

it is detected right, but only first thread is ever used.

top shows at least 50% idle no matter what i run!

what's wrong?

Timecounter "i8254" frequency 1193182 Hz quality 0
CPU: Intel(R) Pentium(R) 4 CPU 3.00GHz (3000.13-MHz K8-class CPU)
   Origin = "GenuineIntel"  Id = 0xf62  Stepping = 2

   AMD Features=0x20100800<SYSCALL,NX,LM>
   AMD Features2=0x1<LAHF>
   Logical CPUs per core: 2
real memory  = 1072562176 (1022 MB)
avail memory = 1021456384 (974 MB)
ACPI APIC Table: <PTLTD          APIC  >
FreeBSD/SMP: Multiprocessor System Detected: 2 CPUs
  cpu0 (BSP): APIC ID:  0
  cpu1 (AP): APIC ID:  1
ioapic0 <Version 2.0> irqs 0-23 on motherboard
acpi0: <PTLTD   RSDT> on motherboard
acpi0: Power Button (fixed)
Timecounter "ACPI-fast" frequency 3579545 Hz quality 1000
acpi_timer0: <24-bit timer at 3.579545MHz> port 0x1008-0x100b on acpi0
cpu0: <ACPI CPU> on acpi0
acpi_throttle0: <ACPI CPU Throttling> on cpu0
cpu1: <ACPI CPU> on acpi0
acpi_throttle1: <ACPI CPU Throttling> on cpu1
acpi_throttle1: failed to attach P_CNT
device_attach: acpi_throttle1 attach returned 6

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