HyperThreading CPU's
Marius M. Rex MARIUS
marius at mail.communityconnect.com
Mon Mar 15 13:32:13 PST 2004
As I tried to state earlier, I see both logical CPU's in my bootup
messages. I likewise see the HTT feature listed in the output. But I do NOT
see the sysctl variable, it is still an unknown oid. I believe both CPUs
are enabled, but since I cannot find the sysctl oid that is mentioned in
UPDATING I wanted to double check.
*snip*
CPU: Intel(R) Pentium(R) 4 CPU 2.60GHz (2595.58-MHz 686-class CPU)
Origin = "GenuineIntel" Id = 0xf29 Stepping = 9
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>
Hyperthreading: 2 logical CPUs
real memory = 1073676288 (1048512K bytes)
avail memory = 1041383424 (1016976K bytes)
Changing APIC ID for IO APIC #0 from 0 to 2 on chip
Programming 24 pins in IOAPIC #0
IOAPIC #0 intpin 2 -> irq 0
FreeBSD/SMP: Multiprocessor motherboard: 2 CPUs
cpu0 (BSP): apic id: 0, version: 0x00050014, at 0xfee00000
cpu1 (AP): apic id: 1, version: 0x00050014, at 0xfee00000
io0 (APIC): apic id: 2, version: 0x00178020, at 0xfec00000
Preloaded elf kernel "kernel" at 0xc038d000.
Warning: Pentium 4 CPU: PSE disabled
Pentium Pro MTRR support enabled
*snip*
Thanks.
-Marius M. Rex
System Admin.
Community Connect Inc.
marius at mail.communityconnect.com
On Mon, 15 Mar 2004, Vivek Khera wrote:
>
> On Mar 15, 2004, at 3:38 PM, Marius M. Rex MARIUS wrote:
>
> > In my fairly recent version of the UPDATING file for 4.9-stable it
> > states
> > that I have to use sysctl to modify the value of
> > 'machdep.hlt_logical_cpus' to
> > '0' to get all of my logical CPU's enabled under hyperthreading.
> >
> > Is this change still necessary? sysctl spits that oid out as unknown
> > when I try to look at it. I do have similar oids but nothing that
> > matches that
> > value precisely:
>
> The OID only shows up if your CPU reports the "HTT" feature. Look at
> /var/run/dmesg.boot and look for the line "Features=" under the CPU
> information right near the top of the kernel boot messages. One of the
> features should be "HTT".
>
> If you disable hyperthreading in your bios, then it will not be there,
> and the OID will not be there either. later in the kernel boot
> messages it should show the APIC configuration/reprogramming and
> indicate multiple processors are present. I'm not sure if you need to
> enable multiple CPU support for HTT, since both of my HTT machines have
> two physical processors in them. I have never tried it on a single cpu
> box.
>
>
> =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
> Vivek Khera, Ph.D. Khera Communications, Inc.
> Internet: khera at kciLink.com Rockville, MD +1-301-869-4449 x806
> AIM: vivekkhera Y!: vivek_khera http://www.khera.org/~vivek/
>
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