HT not active

HT not active

[Jan Engelhardt]

Hello list,



I cannot get HT to be used on some machine:

w04a# cat /proc/cpuinfo 
processor       : 0
vendor_id       : GenuineIntel
cpu family      : 15
model           : 0
model name      : Intel(R) Pentium(R) 4 CPU 1700MHz
stepping        : 10
cpu MHz         : 1694.890
cache size      : 256 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 up
bogomips        : 3393.46

'ht' indicates:
#define X86_FEATURE_HT          (0*32+28) /* Hyper-Threading */                 

so I installed an SMP kernel, which has
CONFIG_SMP=y
CONFIG_SUSPEND_SMP=y
CONFIG_X86_FIND_SMP_CONFIG=y
CONFIG_SCHED_SMT=y
CONFIG_X86_HT=y

yet it shows the 'up' flag in cpuinfo
#define X86_FEATURE_UP          (3*32+ 9) /* smp kernel running on up */

What could be missing? Some BIOS option perhaps?
Thanks for any hints.


Jan Engelhardt
-- 

Re: HT not active

[Michal Piotrowski]

Hi Jan,

On 14/08/06, Jan Engelhardt <jengelh@linux01.gwdg.de> wrote:
> Hello list,
>
>
>
> I cannot get HT to be used on some machine:
>
> w04a# cat /proc/cpuinfo
> processor       : 0
> vendor_id       : GenuineIntel
> cpu family      : 15
> model           : 0
> model name      : Intel(R) Pentium(R) 4 CPU 1700MHz
> stepping        : 10
> cpu MHz         : 1694.890
> cache size      : 256 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 up
> bogomips        : 3393.46
>
> 'ht' indicates:
> #define X86_FEATURE_HT          (0*32+28) /* Hyper-Threading */
>
> so I installed an SMP kernel, which has
> CONFIG_SMP=y
> CONFIG_SUSPEND_SMP=y
> CONFIG_X86_FIND_SMP_CONFIG=y
> CONFIG_SCHED_SMT=y
> CONFIG_X86_HT=y
>
> yet it shows the 'up' flag in cpuinfo
> #define X86_FEATURE_UP          (3*32+ 9) /* smp kernel running on up */
>
> What could be missing? Some BIOS option perhaps?
> Thanks for any hints.

Do you have CONFIG_NR_CPUS=2 in kernel config?

>
>
> Jan Engelhardt
> --

Regards,
Michal

-- 
Michal K. K. Piotrowski
LTG - Linux Testers Group
(http://www.stardust.webpages.pl/ltg/wiki/)

Re: HT not active

[Jan Engelhardt]

>> What could be missing? Some BIOS option perhaps?
>> Thanks for any hints.
>
> Do you have CONFIG_NR_CPUS=2 in kernel config?

CONFIG_NR_CPUS=32
http://jengelh.hopto.org/w04a.gz


Jan Engelhardt
-- 

Re: HT not active

[Mikael Pettersson]

On Mon, 14 Aug 2006 13:38:22 +0200 (MEST), Jan Engelhardt wrote:
> I cannot get HT to be used on some machine:
> 
> w04a# cat /proc/cpuinfo 
> processor       : 0
> vendor_id       : GenuineIntel
> cpu family      : 15
> model           : 0
> model name      : Intel(R) Pentium(R) 4 CPU 1700MHz
> stepping        : 10
> cpu MHz         : 1694.890
> cache size      : 256 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 up
> bogomips        : 3393.46
> 
> 'ht' indicates:
> #define X86_FEATURE_HT          (0*32+28) /* Hyper-Threading */                 
...
> What could be missing? Some BIOS option perhaps?

The HT cpuid capability flag does not imply that HT actually is present.
You also have to count #siblings. See Intel's IA32 SDM Vol3 for details.

There are often BIOS options to enable or disable HT. However, your model 0
P4 is quite old and probably doesn't have HT.

Re: HT not active

[Keith Owens]

Jan Engelhardt (on Mon, 14 Aug 2006 13:38:22 +0200 (MEST)) wrote:
>Hello list,
>
>
>
>I cannot get HT to be used on some machine:
>
>w04a# cat /proc/cpuinfo 
>processor       : 0
>vendor_id       : GenuineIntel
>cpu family      : 15
>model           : 0
>model name      : Intel(R) Pentium(R) 4 CPU 1700MHz
>stepping        : 10
>cpu MHz         : 1694.890
>cache size      : 256 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 up
>bogomips        : 3393.46
>
>'ht' indicates:
>#define X86_FEATURE_HT          (0*32+28) /* Hyper-Threading */                 
>
>so I installed an SMP kernel, which has
>CONFIG_SMP=y
>CONFIG_SUSPEND_SMP=y
>CONFIG_X86_FIND_SMP_CONFIG=y
>CONFIG_SCHED_SMT=y
>CONFIG_X86_HT=y
>
>yet it shows the 'up' flag in cpuinfo
>#define X86_FEATURE_UP          (3*32+ 9) /* smp kernel running on up */
>
>What could be missing? Some BIOS option perhaps?
>Thanks for any hints.

It could be BIOS HT settings.  You could also need CONFIG_ACPI, I have
seen HT systems which required ACPI before Linux could see the extra
threads.

Re: HT not active

[Alan Cox]

Ar Llu, 2006-08-14 am 13:38 +0200, ysgrifennodd Jan Engelhardt:
> What could be missing? Some BIOS option perhaps?
> Thanks for any hints.

Hyperthreading must be BIOS enabled, its not something Linux can "turn
on". The "ht" flag merely indicates that the processor supports
hyperthreading not that it is enabled.

Re: HT not active

[Jan Engelhardt]

>> What could be missing? Some BIOS option perhaps?

No BIOS option, I looked.

>The HT cpuid capability flag does not imply that HT actually is present.

Wonderful just wonderful.

>There are often BIOS options to enable or disable HT. However, your model 0
>P4 is quite old and probably doesn't have HT.

Dell Precision 330.



Jan Engelhardt
-- 

Re: HT not active

[Robert Hancock]

Jan Engelhardt wrote:
> I cannot get HT to be used on some machine:
> 
> w04a# cat /proc/cpuinfo 
> processor       : 0
> vendor_id       : GenuineIntel
> cpu family      : 15
> model           : 0
> model name      : Intel(R) Pentium(R) 4 CPU 1700MHz
> stepping        : 10
> cpu MHz         : 1694.890
> cache size      : 256 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 up
> bogomips        : 3393.46
> 
> 'ht' indicates:
> #define X86_FEATURE_HT          (0*32+28) /* Hyper-Threading */                 

Most P4s that I have seen have the HT flag but only some of them 
actually support it (and have it enabled in the BIOS). I don't think any 
1.7GHz models did.

-- 
Robert Hancock      Saskatoon, SK, Canada
To email, remove "nospam" from hancockr@nospamshaw.ca
Home Page: http://www.roberthancock.com/

Re: HT not active

[linux-os (Dick Johnson)]

On Mon, 14 Aug 2006, Robert Hancock wrote:

> Jan Engelhardt wrote:
>> I cannot get HT to be used on some machine:
>>
>> w04a# cat /proc/cpuinfo
>> processor       : 0
>> vendor_id       : GenuineIntel
>> cpu family      : 15
>> model           : 0
>> model name      : Intel(R) Pentium(R) 4 CPU 1700MHz
>> stepping        : 10
>> cpu MHz         : 1694.890
>> cache size      : 256 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 up
>> bogomips        : 3393.46
>>
>> 'ht' indicates:
>> #define X86_FEATURE_HT          (0*32+28) /* Hyper-Threading */
>
> Most P4s that I have seen have the HT flag but only some of them
> actually support it (and have it enabled in the BIOS). I don't think any
> 1.7GHz models did.
>
> --
> Robert Hancock      Saskatoon, SK, Canada
> To email, remove "nospam" from hancockr@nospamshaw.ca
> Home Page: http://www.roberthancock.com/

It's mostly a motherboard issue. This board is an Intel motherboard.
However, Intel decided to not allow HT (strange). I tried to
bring the MB back to CompUSA, but they declared; "The board is
not defective. Windows doesn't use hyper threading, and this is
a windows-only board...." They claim no board is compatible with
Linux. They were perfectly willing to give me back my money, but
they would not guarantee that any of their motherboards were
"compatible" with Linux. With an attitude like that, one can
quickly learn where not to buy motherboards.

processor	: 0
vendor_id	: GenuineIntel
cpu family	: 15
model		: 2
model name	: Intel(R) Pentium(R) 4 CPU 2.80GHz
stepping	: 7
cpu MHz		: 2794.381
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	: 5592.62

The solution may be, in the future, to bring a bootable CR/ROM with you
when buying motherboards or CPUs.... and get stuff off the net that's
guaranteed to do what you want. This exact same software, exact same
configuration ".config" file, produces this on another machine:

processor	: 0
vendor_id	: GenuineIntel
cpu family	: 15
model		: 2
model name	: Intel(R) Xeon(TM) CPU 2.40GHz
stepping	: 9
cpu MHz		: 2399.779
cache size	: 512 KB
physical id	: 0
siblings	: 2
core id		: 0
cpu cores	: 1
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	: 4804.62

processor	: 1
vendor_id	: GenuineIntel
cpu family	: 15
model		: 2
model name	: Intel(R) Xeon(TM) CPU 2.40GHz
stepping	: 9
cpu MHz		: 2399.779
cache size	: 512 KB
physical id	: 0
siblings	: 2
core id		: 0
cpu cores	: 1
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	: 4798.06

processor	: 2
vendor_id	: GenuineIntel
cpu family	: 15
model		: 2
model name	: Intel(R) Xeon(TM) CPU 2.40GHz
stepping	: 9
cpu MHz		: 2399.779
cache size	: 512 KB
physical id	: 3
siblings	: 2
core id		: 0
cpu cores	: 1
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	: 4798.06

processor	: 3
vendor_id	: GenuineIntel
cpu family	: 15
model		: 2
model name	: Intel(R) Xeon(TM) CPU 2.40GHz
stepping	: 9
cpu MHz		: 2399.779
cache size	: 512 KB
physical id	: 3
siblings	: 2
core id		: 0
cpu cores	: 1
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	: 4798.09

... so you can see that SMP and hyper-threading are enabled.

Cheers,
Dick Johnson
Penguin : Linux version 2.6.16.24 on an i686 machine (5592.62 BogoMips).
New book: http://www.AbominableFirebug.com/
_
\x1a\x04

****************************************************************
The information transmitted in this message is confidential and may be privileged.  Any review, retransmission, dissemination, or other use of this information by persons or entities other than the intended recipient is prohibited.  If you are not the intended recipient, please notify Analogic Corporation immediately - by replying to this message or by sending an email to DeliveryErrors@analogic.com - and destroy all copies of this information, including any attachments, without reading or disclosing them.

Thank you.

Re: HT not active

[Arjan van de Ven]

On Mon, 2006-08-14 at 13:38 +0200, Jan Engelhardt wrote:
> Hello list,
> 
> 
> 
> I cannot get HT to be used on some machine:
> 
> w04a# cat /proc/cpuinfo 
> processor       : 0
> vendor_id       : GenuineIntel
> cpu family      : 15
> model           : 0
> model name      : Intel(R) Pentium(R) 4 CPU 1700MHz
> stepping        : 10
> cpu MHz         : 1694.890
> cache size      : 256 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 up
> bogomips        : 3393.46
> 
> 'ht' indicates:
> #define X86_FEATURE_HT          (0*32+28) /* Hyper-Threading */                 


the "ht" flag does not mean what you think it means.....
it does NOT mean "I can use hyperthreading on this machine"; it
basically means "the ht cpuid commands work", so that linux can find the
nr of siblings, which can be..... 1
 

Re: HT not active

[Jan Engelhardt]

>
>the "ht" flag does not mean what you think it means.....
>it does NOT mean "I can use hyperthreading on this machine"; it
>basically means "the ht cpuid commands work", so that linux can find the
>nr of siblings, which can be..... 1
> 
Alright. I am just waiting for a CPU which has an XMAS CPUID...


Jan Engelhardt
-- 

Re: HT not active

[Lennart Sorensen]

On Mon, Aug 14, 2006 at 10:51:47AM -0400, linux-os (Dick Johnson) wrote:
> It's mostly a motherboard issue. This board is an Intel motherboard.
> However, Intel decided to not allow HT (strange). I tried to
> bring the MB back to CompUSA, but they declared; "The board is
> not defective. Windows doesn't use hyper threading, and this is
> a windows-only board...." They claim no board is compatible with
> Linux. They were perfectly willing to give me back my money, but
> they would not guarantee that any of their motherboards were
> "compatible" with Linux. With an attitude like that, one can
> quickly learn where not to buy motherboards.

It is both a motherboard (bios actually) and cpu issue.

> processor	: 0
> vendor_id	: GenuineIntel
> cpu family	: 15
> model		: 2
> model name	: Intel(R) Pentium(R) 4 CPU 2.80GHz
> stepping	: 7
> cpu MHz		: 2794.381
> 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	: 5592.62

I have a P4 2.8GHz which does do HT.  It is family 15, model 2, stepping
9.  Stepping 7 is probably from just before intel started enabling HT
support.  The P4A Northwood did not have HT and came in 1.6 to 2.8GHz
(400FSB).  The P4B Northwood did have HT on the 3.06Ghz model only and
came in 2.0 to 3.06Ghz (533FSB).  The P4C Northwood had HT and came
in 2.4 to 3.4GHz (800FSB).  I have the P4C 2.8GHz which is showing as
model 2 stepping 9.

> The solution may be, in the future, to bring a bootable CR/ROM with you
> when buying motherboards or CPUs.... and get stuff off the net that's
> guaranteed to do what you want. This exact same software, exact same
> configuration ".config" file, produces this on another machine:

Who wants to buy a power wasting P4 now, when they can instead get the
Core 2 or an Athlon 64 which run faster using less power?

> processor	: 0
> vendor_id	: GenuineIntel
> cpu family	: 15
> model		: 2
> model name	: Intel(R) Xeon(TM) CPU 2.40GHz
> stepping	: 9
> cpu MHz		: 2399.779
> cache size	: 512 KB
> physical id	: 0
> siblings	: 2
> core id		: 0
> cpu cores	: 1
> 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	: 4804.62

So this is a model 2 stepping 9 just as my P4 is and HT works just like
my P4 does.

I can't actually find a list that says when stepping had what feature
enabled.

--
Len Sorensen

Re: HT not active

[linux-os (Dick Johnson)]

On Mon, 14 Aug 2006, Lennart Sorensen wrote:

> On Mon, Aug 14, 2006 at 10:51:47AM -0400, linux-os (Dick Johnson) wrote:
>> It's mostly a motherboard issue. This board is an Intel motherboard.
>> However, Intel decided to not allow HT (strange). I tried to
>> bring the MB back to CompUSA, but they declared; "The board is
>> not defective. Windows doesn't use hyper threading, and this is
>> a windows-only board...." They claim no board is compatible with
>> Linux. They were perfectly willing to give me back my money, but
>> they would not guarantee that any of their motherboards were
>> "compatible" with Linux. With an attitude like that, one can
>> quickly learn where not to buy motherboards.
>
> It is both a motherboard (bios actually) and cpu issue.
>
>> processor	: 0
>> vendor_id	: GenuineIntel
>> cpu family	: 15
>> model		: 2
>> model name	: Intel(R) Pentium(R) 4 CPU 2.80GHz
>> stepping	: 7
>> cpu MHz		: 2794.381
>> 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	: 5592.62
>
> I have a P4 2.8GHz which does do HT.  It is family 15, model 2, stepping
> 9.  Stepping 7 is probably from just before intel started enabling HT
> support.  The P4A Northwood did not have HT and came in 1.6 to 2.8GHz
> (400FSB).  The P4B Northwood did have HT on the 3.06Ghz model only and
> came in 2.0 to 3.06Ghz (533FSB).  The P4C Northwood had HT and came
> in 2.4 to 3.4GHz (800FSB).  I have the P4C 2.8GHz which is showing as
> model 2 stepping 9.
>
>> The solution may be, in the future, to bring a bootable CR/ROM with you
>> when buying motherboards or CPUs.... and get stuff off the net that's
>> guaranteed to do what you want. This exact same software, exact same
>> configuration ".config" file, produces this on another machine:
>
> Who wants to buy a power wasting P4 now, when they can instead get the
> Core 2 or an Athlon 64 which run faster using less power?

They are now pretty cheap in the USA. Being obsolete by a year
or so gets some good performance at the additional electrical
cost of a nightlight!

>
>> processor	: 0
>> vendor_id	: GenuineIntel
>> cpu family	: 15
>> model		: 2
>> model name	: Intel(R) Xeon(TM) CPU 2.40GHz
>> stepping	: 9
>> cpu MHz		: 2399.779
>> cache size	: 512 KB
>> physical id	: 0
>> siblings	: 2
>> core id		: 0
>> cpu cores	: 1
>> 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	: 4804.62
>
> So this is a model 2 stepping 9 just as my P4 is and HT works just like
> my P4 does.
>
> I can't actually find a list that says when stepping had what feature
> enabled.
>
> --
> Len Sorensen
>

Cheers,
Dick Johnson
Penguin : Linux version 2.6.16.24 on an i686 machine (5592.62 BogoMips).
New book: http://www.AbominableFirebug.com/
_
\x1a\x04

****************************************************************
The information transmitted in this message is confidential and may be privileged.  Any review, retransmission, dissemination, or other use of this information by persons or entities other than the intended recipient is prohibited.  If you are not the intended recipient, please notify Analogic Corporation immediately - by replying to this message or by sending an email to DeliveryErrors@analogic.com - and destroy all copies of this information, including any attachments, without reading or disclosing them.

Thank you.

Re: HT not active

[Len Brown]

On Monday 14 August 2006 08:10, Keith Owens wrote:

> You could also need CONFIG_ACPI, I have
> seen HT systems which required ACPI before Linux could see the extra
> threads.

CONFIG_ACPI=y This is required of all HT systems -- except the odd-bird that enables the
siblings in MPS (usually via BIOS settings) in order to trick out some operating systems.

dmesg for the system will tell us if ACPI sees the siblings or not.

-Len

Re: HT not active

[Lennart Sorensen]

On Mon, Aug 14, 2006 at 12:02:26PM -0400, linux-os (Dick Johnson) wrote:
> They are now pretty cheap in the USA. Being obsolete by a year
> or so gets some good performance at the additional electrical
> cost of a nightlight!

5W != 100W

The athlon 64s look like a very good deal though.

--
Len Sorensen

Re: HT not active

[Jan Engelhardt]

>> They are now pretty cheap in the USA. Being obsolete by a year
>> or so gets some good performance at the additional electrical
>> cost of a nightlight!
>
>5W != 100W

I wonder whether 20 Transmeta 5800 (running at roughly 6W when under 
load) could outperform one Pentium4 ;-)


Jan Engelhardt
-- 

Re: HT not active

[Mark Lord]

Alan Cox wrote:
>
> Hyperthreading must be BIOS enabled, its not something Linux can "turn
> on". The "ht" flag merely indicates that the processor supports
> hyperthreading not that it is enabled.

Not quite.  Even non-HT CPUs report the ht flag (I have one here).
As somebody else said, ht just means the system supports querying
the number of ht "siblings", even though that number might be zero.

Somewhat misleading, though technically accurate.

Cheers

Re: HT not active

[H. Peter Anvin]

Jan Engelhardt wrote:
>>> They are now pretty cheap in the USA. Being obsolete by a year
>>> or so gets some good performance at the additional electrical
>>> cost of a nightlight!
>> 5W != 100W
> 
> I wonder whether 20 Transmeta 5800 (running at roughly 6W when under 
> load) could outperform one Pentium4 ;-)
> 

Don't know about 20 TM5800s, but 12 TM8800s (same power ballpark) 
certainly did...

	-hpa