[plug] hyperthreading

Thu Dec 11 19:13:48 WST 2003

I had a IBM x series server with dual Xeon and I installed RHL8 on it and it was autodetected because I also installed the SMP kernel.  But agin this was because I had dual processors and it showed up as 4 processors.  I did a install of a custom design server with a Pentium-4 2.67GHz 800FSB CPU and it was autodetected with Hyperthreading.  This was because during the installation process it installed the kernel 2.4.20-8smp on the server.
What is the verion of your kernel (uname -a)?

Jon

Jon L. Miller, MCNE, CNS, ASE
Director/Sr Systems Consultant
MMT Networks Pty Ltd
http://www.mmtnetworks.com.au

"I don't know the key to success, but the key to failure
 is trying to please everybody." -Bill Cosby

>>> schlegel at cs.curtin.edu.au 10:06:39 am 11/12/2003 >>>
Hi Jon

It seems these requirements are necessary to have Hyper Threading
working

1) The processor must support it (Mobile Pentium 4-M, others supporting
HT)
1.5) The Intel Chipset must support it (>= Intel 865, 875)
2) The BIOS must support it

Its seems, in my case, not all requirements are met, so no luck here.

Kind regards

Sacha

On Thu, 2003-12-11 at 07:01, jlmiller at mmtnetworks.com.au wrote:
> Linux* Issues with Hyper-Threaded Technology
> For Linux to make use of HT Technology an SMP kernel must be
> installed. This is confirmed by the output of uname -a, which shows
> the kernel version ending in SMP. The output of cat /proc/cpuinfo (see
> below) will show the number of CPU's and their properties. HT
> Technology is shown by the presence of the ht flag. If the computer
> BIOS supports SMP (or an analogous option is activated in BIOS), the
> machine can be used as an SMP system with Linux. When the SMP kernel
> is installed, it will seem as if double the physical processors are
> available. At present the errata kernels 2.4.9-21 and 2.4.9-31 have HT
> Technology support, but you have to pass "acpismp=force" on the kernel
> command line to enable it.
> 
> 
> 
> 
> 
> 
> > $cat /proc/cpuinfo
> > processor : 0
> > vendor_id : GenuineIntel
> > cpu family : 15
> > model : 1
> > model name : Intel(R) Pentium(R) 4 CPU 1.70GHz
> > stepping : 2
> > cpu MHZ : 1694.907
> > 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
> > bogomips : 3381.65
> >
> 
> 
> 
> 
> The Linux 2.4 kernel will not be developed to take an active advantage
> of HT Technology and patches may be required to fix some possible
> problems. Rusty Russell (a Linux developer) mentions: "The
> hyperthreading issue... is likely to throw a new set of complications
> into the mix. A processor which does hyperthreading looks like two
> independent CPUs, but it [processes] should not be scheduled [by the
> scheduler] as such - it is better to divide process across real
> (hardware) processors first."
> 
> Work is underway in the Linux community to add HT Technology patches
> to the 2.4 release of the Linux kernel. HT Technology changes to Linux
> are being exploited by Carrier Grade Linux Change Project under the
> ODSL (see below). HT Technology offers performance enhancement
> potentials that are a prime requirement of the carrier grade
> environment. Active utilization of HT Technology will likely appear in
> the standard 2.5 Linux kernel, although it has not yet been placed
> into the development queue due to prerequisite work being done.
> 
> 
> Linux HT Technology Capable Compilers
> The Intel Linux C++ Compiler 6.0 has increased levels of Linux and
> industry standards support that provide improved compatibility with
> GNU C, broader support of Linux distributions, support for the C++ ABI
> object model and GNU inline ASM for IA32. - The Intel C++ Compiler
> supports OpenMP API version 1.0 and performs code transformation for
> shared memory parallel programming. The Intel compiler supports
> multi-threaded application development and debugging, with support for
> OpenMP 1.0 for C and new support for OpenMP 1.0 for C++. This makes it
> fully capable of designing HT Technology enabled applications on HT
> Technology enabled hardware.
> 
> Taken from Intel's website, search enable hyperthreading, linux
>  
> Jon
>  
> Jon L. Miller, MCNE, CNS, ASE
> Director/Sr Systems Consultant
> MMT Networks Pty Ltd
> http://www.mmtnetworks.com.au 
>  
> "I don't know the key to success, but the key to failure
>  is trying to please everybody." -Bill Cosby
>  
>  
> >>> smclevie at ozemail.com.au 2:44:35 pm 10/12/2003 >>>
> Hi all,
> 
> I wonder if someone could inform me of the necessary steps to enable 
> hyperthreading (P4 2.4G Pentium)?
> 
> I thought I had enabled the option in a kernel build ...
> 
> I would like to see two tuxes at the top of screen also.
> 
> Thank you,
> 
> Steve. 
> 
> 
> _______________________________________________
> plug mailing list
> plug at plug.linux.org.au 
> http://mail.plug.linux.org.au/cgi-bin/mailman/listinfo/plug 
-- 
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Sacha                                   Schlegel
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4 Warwick Str, 6102 St. James, Perth,  Australia
sacha at schlegel.li                www.schlegel.li 
public key:            www.schlegel.li/sacha.gpg 
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-- 
------------------------------------------------
Sacha                                   Schlegel
------------------------------------------------
4 Warwick Str, 6102 St. James, Perth,  Australia
sacha at schlegel.li                www.schlegel.li 
public key:            www.schlegel.li/sacha.gpg 
------------------------------------------------