# cat /proc/cpuinfo

## lavacano

cat /proc/cpuinfo output reads:

processor       : 0

vendor_id       : GenuineIntel

cpu family      : 15

model           : 2

model name      : Intel(R) Pentium(R) 4 CPU 2.40GHz

stepping        : 7

cpu MHz         : 2400.455

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 sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe cid xtpr

bogomips        : 4734.97

now my compo http://support.gateway.com/support/allsysteminfo.asp?sn=0029146985

doesnt advertise hyperthreading... but thats what I was wondering guys if I enable SMP in my kernel and what not would my compo hyperthread?

thanks!

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## zieloo

 *lavacano wrote:*   

> cat /proc/cpuinfo output reads:
> 
> processor       : 0
> 
> vendor_id       : GenuineIntel
> ...

 

Yes, your CPU supports HT, it's the first model that do so;-) First meaning the slowest.

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## syg00

 *lavacano wrote:*   

> ... but thats what I was wondering guys if I enable SMP in my kernel and what not would my compo hyperthread?

 Maybe, maybe not.

Depends mainly on whether you have H/T support in the BIOS. Shouldn't take much to check.

For example, on one of my mobo's, I had to flash the BIOS to get my chip to run H/T. Prior to that, would only run as 1 CPU.

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## lavacano

 *syg00 wrote:*   

>  *lavacano wrote:*   ... but thats what I was wondering guys if I enable SMP in my kernel and what not would my compo hyperthread? Maybe, maybe not.
> 
> Depends mainly on whether you have H/T support in the BIOS. Shouldn't take much to check.
> 
> For example, on one of my mobo's, I had to flash the BIOS to get my chip to run H/T. Prior to that, would only run as 1 CPU.

 

Shitty deal cause I need win XP to flash bios.  Unless you have a workkaround http://support.intel.com/support/motherboards/desktop/d845grg/ ... 

the downloads are here: link

I wonder if there is some way to extract the bin then dd it to nvram?

Fixed long link - tomk

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## syg00

Have a look at my last post here

Should do the job - just pull the DOS installer from Intel.

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## lavacano

wow I didnt know linux had like a type of background floppy hardware kernel access-thingy cupled with dd its like really multitasking cant wait till I get HT too.  That could also be famous last words.  Lets all cross our fingers and take a deep breath now, be back later today.

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## lavacano

OK!  everything went good, anyway to see now if ht will work or do I need to enable SMP STAT?  BTW:  It was a lot easier than I thought, I thought it wouldnt flash over gateway's bios but low;  It worked, completely different BIOS!

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## Sm1

Sorry to bump such an old thread here, but I am wondering myself about some ht stuff.

I have a Pentium D 2.8Ghz and intel D945Psn.

I compiled a SMP kernel and both cores are recognized

```
supermario@supermario ~/gnome-keybindings-0.1.0 $ cat /proc/cpuinfo

processor       : 0

vendor_id       : GenuineIntel

cpu family      : 15

model           : 4

model name      :               Intel(R) Pentium(R) D CPU 2.80GHz

stepping        : 4

cpu MHz         : 2800.123

cache size      : 1024 KB

physical id     : 0

siblings        : 2

core id         : 0

cpu cores       : 2

fpu             : yes

fpu_exception   : yes

cpuid level     : 5

wp              : yes

flags           : 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 ht tm syscall nx lm constant_tsc pni monitor ds_cpl cid cx16 xtpr

bogomips        : 5616.70

clflush size    : 64

cache_alignment : 128

address sizes   : 36 bits physical, 48 bits virtual

power management:

processor       : 1

vendor_id       : GenuineIntel

cpu family      : 15

model           : 4

model name      :               Intel(R) Pentium(R) D CPU 2.80GHz

stepping        : 4

cpu MHz         : 2800.123

cache size      : 1024 KB

physical id     : 0

siblings        : 2

core id         : 1

cpu cores       : 2

fpu             : yes

fpu_exception   : yes

cpuid level     : 5

wp              : yes

flags           : 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 ht tm syscall nx lm constant_tsc pni monitor ds_cpl cid cx16 xtpr

bogomips        : 5599.31

clflush size    : 64

cache_alignment : 128

address sizes   : 36 bits physical, 48 bits virtual

power management:

```

Now oddly enough both cores also claim to have a ht flag.  I was under the assumption that ht was only possible on the extreme edition of the proc.  I don't see any options in the bios for ht, but is it possible that it can be enabled someway?

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## guero61

If /proc/cpuinfo shows two processors, it's already enabled.

FWIW, HT won't get you much of anything other than some marginal responsiveness (think hardware-level pre-emption).  It also has some race conditions where processes on one of the virtual cores can read what's in the cache for the other one, exposing encryption keys and such.

On all my servers, regardless of capability, HT is turned off.  I think if I had it on my desktop, I'd nuke it there too, but that's just me.

----------

## Sm1

Well I was under the assumption that I was seeing 2 procs because of the two cores, not because of HT.  I guess better worded, would it be worth it to try to get HT to work so that I would have another 2 virtual cores?

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## guero61

So you already have two distinct processors and are wondering if it's worth your while to enable HT, if I understand correctly.  BTW - most P4 cores are HT capable, lately.

It really depends on what _you_ want to do, but I really see little value in enabling HT on other than a single-processor desktop that's shooting for greater responsiveness.  Otherwise, you're just robbing Peter to pay Paul at the expense of security - not a worthwhile venture, in my book.  HT is not like the dual-core Opterons, where you'll get something like 95-97% x 2 (190+%) throughput/performance.  Instead, you get more along the lines of 49% x 2.

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## larand54

Does this mean that th cpu may handlehyperthreading?

```

processor       : 0

vendor_id       : GenuineIntel

cpu family      : 15

model           : 2

model name      : Intel(R) Pentium(R) 4 CPU 2.66GHz

stepping        : 9

cpu MHz         : 2665.754

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 sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe cid xtpr

bogomips        : 5340.56

```

The motherboard ASUS-P4P800S claims to support HT but does not give me any way to enable it.

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## guero61

If it says it supports HT, then it's probably enabled by default with no way to twiddle it.

For the record, if the command "cat /proc/cpuinfo" shows the flag "HT" (case-insensitive) in the "flags" section, you have a processor that at least presents itself to the OS as hyperthreading capable.

----------

