# No HT on an HT Cpu?

## ravensix

I have a Xeon 3GHz with HT. I enabled SMP in the kernel and SMT as well. I notice this in the bootup

 *Quote:*   

> WARNING: 1 siblings found for CPU0, should be 2

 

I'm assuming there should be 2 siblings on CPU0(aka HT) but its not enabling it, anyone help me on there?

EIDT: HT iis enabled in the bios

----------

## ravensix

*bump*

----------

## kenyon

No, HT will show up as two processors, i.e. CPU0 and CPU1 (at least that's how it is with my Pentium 4 with kernel 2.6.9-cko3).  What does /proc/cpuinfo show?

----------

## ravensix

No, theres only 1 cpu shown, its like it can't bring up the 2nd cpu

----------

## kenyon

So, I think there's something wrong.  :Wink:   All I can suggest is to try different kernels and patchsets.  Looks like you have a similar setup to mine, with HT, Reiser4, NPTL, etc.  The 2.6.9-cko3 kernel was the only one I could even use at all, all others would crash.  Haven't tried any 2.6.10 though, there is a cko1 for 2.6.10, you might try that.

Just for fun, here's everything which is set in the processor type and features section of my kernel config:

```
#

# Processor type and features

#

CONFIG_X86_PC=y

CONFIG_MPENTIUM4=y

CONFIG_X86_CMPXCHG=y

CONFIG_X86_XADD=y

CONFIG_X86_L1_CACHE_SHIFT=7

CONFIG_RWSEM_XCHGADD_ALGORITHM=y

CONFIG_X86_WP_WORKS_OK=y

CONFIG_X86_INVLPG=y

CONFIG_X86_BSWAP=y

CONFIG_X86_POPAD_OK=y

CONFIG_X86_GOOD_APIC=y

CONFIG_X86_INTEL_USERCOPY=y

CONFIG_X86_USE_PPRO_CHECKSUM=y

CONFIG_HPET_TIMER=y

CONFIG_SMP=y

CONFIG_NR_CPUS=2

CONFIG_SCHED_SMT=y

CONFIG_PREEMPT=y

CONFIG_PREEMPT_BKL=y

CONFIG_X86_LOCAL_APIC=y

CONFIG_X86_IO_APIC=y

CONFIG_X86_TSC=y

CONFIG_X86_MCE=y

CONFIG_X86_MCE_NONFATAL=y

CONFIG_X86_MCE_P4THERMAL=y
```

And here's what cat /proc/cpuinfo shows:

```
processor   : 0

vendor_id   : GenuineIntel

cpu family   : 15

model      : 2

model name   : Intel(R) Pentium(R) 4 CPU 2.80GHz

stepping   : 9

cpu MHz      : 2807.351

cache size   : 512 KB

physical id   : 0

siblings   : 2

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   : 5537.79

processor   : 1

vendor_id   : GenuineIntel

cpu family   : 15

model      : 2

model name   : Intel(R) Pentium(R) 4 CPU 2.80GHz

stepping   : 9

cpu MHz      : 2807.351

cache size   : 512 KB

physical id   : 0

siblings   : 2

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   : 5603.32
```

----------

## sn4ip3r

Has HT worked before? In windows perhaps?

If it has never worked perhaps a bios update can help?

----------

## ravensix

Yeah, before i installed Gentoo on the server, it had FreeBSD, and HT worked on it.

----------

## ravensix

 *kenyon wrote:*   

> 
> 
> ```
> #
> 
> ...

 

I don't have quite a bit of those, like generic x86 support, HPET, i don't have preemptive because i heard thats for desktops, and this is a server, so i don't think those would help much

----------

## ravensix

i added generic x86 support, prempt, and HPET support, still no go however

----------

## ravensix

*bump*

----------

## ravensix

So no one has Gentoo installed on a Xeon server with HT? ;o

----------

## sn4ip3r

 *ravensix wrote:*   

> So no one has Gentoo installed on a Xeon server with HT? ;o

 

I have a server with two HT-capable Xeons and HT does work fine. Currently running kernel 2.6.10 but it also worked fine with 2.6.8.1 and 2.6.9.

----------

## snekiepete

Make sure you have acpi enabled and not apm (it disables smp), and that you dont have the noacip option in your grub line....just something to check.

----------

## malloc

Does your motherboard support HT? There are some boards that don't.

----------

## ravensix

As mentioned, before i installed gentoo, it had FreeBSD running just fine, i'll install ACPI in the kernel and try it out.

----------

## og-phantom

 *ravensix wrote:*   

> So no one has Gentoo installed on a Xeon server with HT? ;o

 

hi, this might not help, but AFAIK you need to have both SMP and SMT enabled in the kernel config... If you just have SMP enabled, i don't think it will pick up the logical processor....

----------

## ravensix

 *og-phantom wrote:*   

>  *ravensix wrote:*   So no one has Gentoo installed on a Xeon server with HT? ;o 
> 
> hi, this might not help, but AFAIK you need to have both SMP and SMT enabled in the kernel config... If you just have SMP enabled, i don't think it will pick up the logical processor....

 

Yeah, i have it enabled, both of them, still no go.

----------

## ravensix

Update: we wiped Gentoo and reinstalled FreeBSD and FreeBSD see and enabled HT, so i dunno wtf is going on.

----------

## ravensix

ANyone with any clues? we're about to reinstall gentoo soon, any clue which kernel i should use? tried 2.6.10-ck1, 2.6.9-gentoo-r13, and the livecd's 2.6.9-gentoo-r1 or whatevers on 2004.3 minimal.

----------

## Leffe

Did ACPI work? HT can't be enabled if ACPI isn't enabled.

----------

## ravensix

Not trrue, when he had slackware there was no ACPI and HT worked fine.

Same for FreeBSD

----------

## thecrazyperson_ws

 *ravensix wrote:*   

> ANyone with any clues? we're about to reinstall gentoo soon, any clue which kernel i should use? tried 2.6.10-ck1, 2.6.9-gentoo-r13, and the livecd's 2.6.9-gentoo-r1 or whatevers on 2004.3 minimal.

 

2.6.10-nitro2!  

go here :  2.6.10-bk3-ck1-nitro2 forum page 

----------

## ravensix

We fixed the problem, got a different server, true dual xeon server. and its all working, cat /proc/cpuinfo shows 4 cpus. Thanks for the help though, oh, and nitro is a home brew that tends to be unstable, and it not for production servers.

----------

## groovec

We have the same Problem here with a Intel(R) Xeon(TM) CPU 3.00GHz in an IBM xServer

it has ht and everything is checked in the kernel config but /proc/cpuinfo shows only 1 cpu and dmesg shows "WARNING: 1 siblings found for CPU0, should be 2"

kernel is 2.6.11-gentoo-r11, is this a bug in the kernel?

a patched kernel is no option on this production server

----------

## Ma3oxuct

Perhaps this is a bug that you may wish to file with the Kernel devs.

```
cat /usr/src/linux/REPORTING-BUGS
```

From what I see, HT does not work for single Xeon cpus.

----------

## bollucks

Try increasing the number of cpus in the config from 2 to 8. Sometimes for complicated acpi reasons they don't enumerate as 0 and 1 and configuring for 2 may miss the second one.

----------

## groovec

it is on the default value 8

----------

## bollucks

Try the bootparam "acpi=forceht"

----------

## groovec

i had a chance today to reboot the server and i tryed it, but same as before, only 1 cpu.

i also double checked everything in the bios and there is ht enabled. as soon as i have some time i will write an kernel bug report.

----------

## magic919

I'm running 2.6.11-gentoo-r11 on my dual HT Xeon server and get 4 cpus.  I'll give it a try on my single HT Xeon and see how that goes.

----------

## magic919

Have put 2.6.12-gentoo-r4 on my single HT 2.4 Xeon and get two CPUs.

----------

## zambizzi

see here:

http://kerneltrap.org/mailarchive/1/message/76871/flat

I had the same problem, re-compiled w/ ACPI support...and life is good again.

----------

## frilled

I have HT running with kernels from 2.6.11 up on multiple Xeons (HP ProLiants to be precise). It has always worked since 2.6 for me... ACPI is enabled, SMP and HT support are in, of course.

----------

