Top only showing one active CPU on HTT system

Jonathan M. Slivko freebsd-lists at slivko.org
Tue May 24 08:58:34 PDT 2005


Actually, I have a similar issue on a Pentium 4 box that's supposedly HT:

CPU: Intel(R) Pentium(R) 4 CPU 2.40GHz (2410.53-MHz 686-class CPU)
   Origin = "GenuineIntel"  Id = 0xf41  Stepping = 1
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>

By the fact that HTT is there in the features, I'm assuming that HT 
support is actually present. Though when I compile my kernel with SMP 
support, it doesn't show up. I've had the box checked in the BIOS for HT 
settings,  but apparently there are none.

Any ideas?

Kirk Strauser wrote:
> I'm running a 5.4-STABLE system (updated as of May 16).  My kernel is 
> basically GENERIC with a few small tweaks, like commenting out extraneous 
> "cpu" lines and adding "options SMP".
> 
> My problem is that although dmesg shows every sign of having launched both 
> logical CPUs:
> 
> $ dmesg | grep -i cpu
> CPU: Intel(R) Xeon(TM) CPU 2.40GHz (2392.05-MHz 686-class CPU)
>   Hyperthreading: 2 logical CPUs
> FreeBSD/SMP: Multiprocessor System Detected: 2 CPUs
>  cpu0 (BSP): APIC ID:  0
>  cpu1 (AP): APIC ID:  1
> cpu0: <ACPI CPU> on acpi0
> cpu1: <ACPI CPU> on acpi0
> SMP: AP CPU #1 Launched!
> 
> ... running "top" only shows "0" in the CPU column for every task.  I don't 
> see anything out of place in sysctl:
> 
> $ sysctl -a | grep -i hlt
> machdep.cpu_idle_hlt: 1
> machdep.hlt_cpus: 2
> machdep.hlt_logical_cpus: 0
> 
> and /boot/loader.conf is all but empty.  Honestly, I don't really know how 
> long this has been going on.  top used to show both 0 and 1 in the C column 
> and I'm not exactly sure when it stopped.  Any ideas?

-- 
  Jonathan M. Slivko - jonathan at slivko.org
"Linux: The Choice for the GNU Generation"
          - http://www.linux.org/ -

Don't fear the penguin.
          .^.
          /V\
        /(   )\
         ^^-^^
   He's here to help.


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