Hyperthread without BIOS enable

Rick Wagner wagnerric at condor.cxo.cpqcorp.net
Fri Jan 21 00:02:09 UTC 2005


I have a P4 system, which >>appears<< to be HT capable.  However, the BIOS 
(newest from vendor) does not give the option of turning HT on.  Without 
support from the BIOS, can HT be forced?  Or am I mis-reading the info below, 
and my CPU really is not HT capable.

BTW, I tested with 2.6.10-1.741_FC3smp, and tried "acpismp=force" (as 
described below).

Thanks,
 --rick

-----------------

With dmesg, I get:

CPU: After generic identify, caps: bfebfbff 00000000 00000000 00000000
CPU: After vendor identify, caps:  bfebfbff 00000000 00000000 00000000
CPU: Trace cache: 12K uops, L1 D cache: 8K
CPU: L2 cache: 512K
CPU: Hyper-Threading is disabled
CPU: After all inits, caps:        bfebf3ff 00000000 00000000 00000080
Intel machine check architecture supported.
Intel machine check reporting enabled on CPU#0.
CPU0: Intel P4/Xeon Extended MCE MSRs (12) available
CPU0: Thermal monitoring enabled
Enabling fast FPU save and restore... done.
Enabling unmasked SIMD FPU exception support... done.
Checking 'hlt' instruction... OK.
CPU0: Intel(R) Pentium(R) 4 CPU 2.66GHz stepping 09
per-CPU timeslice cutoff: 1463.05 usecs.
task migration cache decay timeout: 2 msecs.
Total of 1 processors activated (5259.26 BogoMIPS).



/proc/cpuinfo says:

processor       : 0
vendor_id       : GenuineIntel
cpu family      : 15
model           : 2
model name      : Intel(R) Pentium(R) 4 CPU 2.66GHz
stepping        : 9
cpu MHz         : 2660.819
cache size      : 512 KB
fdiv_bug        : no
hlt_bug         : no
f00f_bug        : no
coma_bug        : no
fpu             : yes
fpu_exception   : yes
cpuid level     : 2
wp              : yes
flags           : fpu vme de pse tsc msr pae mce cx8 apic mtrr pge mca cmov 
patpse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe cid xtpr
                                               ^^
bogomips        : 5259.26


and dmidecode says:

Handle 0x0005
        DMI type 4, 35 bytes.
        Processor Information
                Socket Designation: XU1 PROCESSOR
                Type: Central Processor
                Family: Pentium 4
                Manufacturer: Intel
                ID: 29 0F 00 00 FF FB EB BF
                Signature: Type 0, Family F, Model 2, Stepping 9
                Flags:
                        FPU (Floating-point unit on-chip)
                        VME (Virtual mode extension)
                        DE (Debugging extension)
                        PSE (Page size extension)
                        TSC (Time stamp counter)
                        MSR (Model specific registers)
                        PAE (Physical address extension)
                        MCE (Machine check exception)
                        CX8 (CMPXCHG8 instruction supported)
                        APIC (On-chip APIC hardware supported)
                        SEP (Fast system call)
                        MTRR (Memory type range registers)
                        PGE (Page global enable)
                        MCA (Machine check architecture)
                        CMOV (Conditional move instruction supported)
                        PAT (Page attribute table)
                        PSE-36 (36-bit page size extension)
                        CLFSH (CLFLUSH instruction supported)
                        DS (Debug store)
                        ACPI (ACPI supported)
                        MMX (MMX technology supported)
                        FXSR (Fast floating-point save and restore)
                        SSE (Streaming SIMD extensions)
                        SSE2 (Streaming SIMD extensions 2)
                        SS (Self-snoop)
>>>                  HTT (Hyper-threading technology)
                        TM (Thermal monitor supported)
                        SBF (Signal break on FERR)
                Version: Intel(R) Pentium(R) 4 CPU 2.66GHz
                Voltage: 1.5 V
                External Clock: 533 MHz
                Max Speed: 3200 MHz
                Current Speed: 2666 MHz
                Status: Populated, Enabled
                Upgrade: Socket 478
                L1 Cache Handle: 0x0006
                L2 Cache Handle: 0x0007
                L3 Cache Handle: Not Provided
                Serial Number: Not Specified
                Asset Tag: Not Specified
                Part Number: Not Specified



Googling came up with references to using acpismp=force, but they seemed to be 
in context of 2.4.* and 2.5.* kernels; didn't see anything wrt 2.6.*.




More information about the fedora-list mailing list